Prefix Sum Interview Questions

Rank

#912MediumFrequency: 87.7%

Random Pick with Weight

Array Math Binary Search Prefix Sum Randomized

Rank

#560MediumFrequency: 87.2%

Subarray Sum Equals K

Rank

#253MediumFrequency: 83.8%

Meeting Rooms II

Array Two Pointers Greedy Sorting Heap (Priority Queue)Prefix Sum

Rank

#1046MediumFrequency: 83.2%

Max Consecutive Ones III

Rank

#2691MediumFrequency: 80.7%

Count Vowel Strings in Ranges

Rank

#238MediumFrequency: 76%

Product of Array Except Self

Rank

#1695MediumFrequency: 73.2%

Maximum Sum Obtained of Any Permutation

Rank

#713MediumFrequency: 66.4%

Subarray Product Less Than K

Rank

#2002HardFrequency: 65.2%

Stone Game VIII

Array Math Dynamic Programming Minimax Prefix Sum Game Theory Zero-Sum Game

#10

Rank

#1219MediumFrequency: 62.5%

Longest Well-Performing Interval

Array Hash Table Stack Monotonic Stack Prefix Sum

#11

Rank

#2466HardFrequency: 62.5%

Maximum Segment Sum After Removals

Array Union-Find Prefix Sum Ordered Set

#12

Rank

#3974MediumFrequency: 62.5%

XOR After Range Multiplication Queries I

Array Divide and Conquer Simulation Prefix Sum

#13

Rank

#3975HardFrequency: 62.5%

XOR After Range Multiplication Queries II

Array Divide and Conquer Prefix Sum

#14

Rank

#523MediumFrequency: 59.8%

Continuous Subarray Sum

Array Hash Table Math Prefix Sum Pigeonhole Principle

#15

Rank

#3880MediumFrequency: 59.6%

Minimum Time to Visit All Houses

#16

Rank

#2249MediumFrequency: 59.3%

Count the Hidden Sequences

#17

Rank

#410HardFrequency: 57.6%

Split Array Largest Sum

Array Binary Search Dynamic Programming Greedy Prefix Sum

#18

Rank

#1016MediumFrequency: 57%

Subarray Sums Divisible by K

#19

Rank

#3789HardFrequency: 55%

Maximize Subarrays After Removing One Conflicting Pair

Array Segment Tree Enumeration Prefix Sum

#20

Rank

#2676MediumFrequency: 54.4%

Find the Score of All Prefixes of an Array

#21

Rank

#3327HardFrequency: 54.4%

Minimum Moves to Pick K Ones

#22

Rank

#525MediumFrequency: 53.4%

Contiguous Array

#23

Rank

#3271MediumFrequency: 53.4%

Count the Number of Houses at a Certain Distance I

Breadth-First Search Graph Theory Prefix Sum

#24

Rank

#3310HardFrequency: 53.4%

Count the Number of Houses at a Certain Distance II

Graph Theory Prefix Sum

#25

Rank

#2574HardFrequency: 52.4%

Count Subarrays With Median K

#26

Rank

#303EasyFrequency: 51.8%

Range Sum Query - Immutable

Array Design Prefix Sum

#27

Rank

#1966MediumFrequency: 51.8%

Frequency of the Most Frequent Element

Array Binary Search Greedy Sliding Window Sorting Prefix Sum

#28

Rank

#209MediumFrequency: 51.4%

Minimum Size Subarray Sum

#29

Rank

#2075MediumFrequency: 51.4%

Brightest Position on Street

Array Sorting Prefix Sum Ordered Set

#30

Rank

#1985MediumFrequency: 49.9%

Maximum Subarray Min-Product

Array Stack Monotonic Stack Prefix Sum Cartesian Tree

#31

Rank

#3034EasyFrequency: 49.9%

Points That Intersect With Cars

#32

Rank

#3751MediumFrequency: 48.9%

Maximum Frequency After Subarray Operation

Array Hash Table Dynamic Programming Greedy Enumeration Prefix Sum

#33

Rank

#2165MediumFrequency: 47.7%

Plates Between Candles

Array String Binary Search Prefix Sum

#34

Rank

#1940MediumFrequency: 47.5%

Maximum XOR for Each Query

#35

Rank

#3475MediumFrequency: 47.5%

Minimum Operations to Make Binary Array Elements Equal to One I

Array Bit Manipulation Queue Sliding Window Prefix Sum

#36

Rank

#3980MediumFrequency: 47.5%

Best Time to Buy and Sell Stock using Strategy

#37

Rank

#3715MediumFrequency: 47.3%

Maximum Coins From K Consecutive Bags

Array Binary Search Greedy Sliding Window Sorting Prefix Sum

#38

Rank

#1603EasyFrequency: 47%

Running Sum of 1d Array

#39

Rank

#3639MediumFrequency: 46.7%

Zero Array Transformation I

#40

Rank

#1693EasyFrequency: 44.7%

Sum of All Odd Length Subarrays

#41

Rank

#4149MediumFrequency: 44.7%

Minimum Increase to Maximize Special Indices

Array Dynamic Programming Greedy Prefix Sum

#42

Rank

#1370MediumFrequency: 44%

Count Number of Nice Subarrays

Array Hash Table Math Sliding Window Prefix Sum

#43

Rank

#1184MediumFrequency: 43.2%

Car Pooling

Array Sorting Heap (Priority Queue)Simulation Prefix Sum

#44

Rank

#2334HardFrequency: 43%

Number of Flowers in Full Bloom

Asked at Databricks

Array Hash Table Binary Search Sorting Prefix Sum Ordered Set

#45

Rank

#724EasyFrequency: 42%

Find Pivot Index

#46

Rank

#2368HardFrequency: 40.2%

Sum of Total Strength of Wizards

Array Stack Monotonic Stack Prefix Sum

#47

Rank

#1783MediumFrequency: 39.2%

Ways to Make a Fair Array

Asked at DoorDash

#48

Rank

#3643MediumFrequency: 39%

Zero Array Transformation II

#49

Rank

#689HardFrequency: 36.8%

Maximum Sum of 3 Non-Overlapping Subarrays

Array Dynamic Programming Sliding Window Prefix Sum

#50

Rank

#966MediumFrequency: 36.3%

Binary Subarrays With Sum

Array Hash Table Sliding Window Prefix Sum

#51

Rank

#1983EasyFrequency: 35.7%

Maximum Population Year

Array Counting Prefix Sum

#52

Rank

#325MediumFrequency: 35%

Maximum Size Subarray Sum Equals k

#53

Rank

#2538HardFrequency: 33.3%

Minimum Cost to Make Array Equal

#54

Rank

#1477MediumFrequency: 33%

Product of the Last K Numbers

Array Math Design Data Stream Prefix Sum

#55

Rank

#1895MediumFrequency: 31.8%

Minimum Number of Operations to Move All Balls to Each Box

#56

Rank

#3265MediumFrequency: 31.8%

Maximum Good Subarray Sum

#57

Rank

#2730MediumFrequency: 31.3%

Maximum OR

Array Greedy Bit Manipulation Prefix Sum

#58

Rank

#1805HardFrequency: 31.1%

Minimum Adjacent Swaps for K Consecutive Ones

#59

Rank

#1833EasyFrequency: 30.4%

Find the Highest Altitude

#60

Rank

#304MediumFrequency: 30.4%

Range Sum Query 2D - Immutable

Array Design Matrix Prefix Sum

#61

Rank

#1694MediumFrequency: 30.2%

Make Sum Divisible by P

#62

Rank

#1537EasyFrequency: 29.7%

Maximum Score After Splitting a String

#63

Rank

#2059MediumFrequency: 29.7%

Unique Length-3 Palindromic Subsequences

Array Binary Search Design Segment Tree Prefix Sum Ordered Set

#64

Rank

#731MediumFrequency: 29.5%

My Calendar II

Asked at Apple

#65

Rank

#892HardFrequency: 29.1%

Shortest Subarray with Sum at Least K

Array Binary Search Queue Sliding Window Heap (Priority Queue)Prefix Sum Monotonic Queue

#66

Rank

#3622MediumFrequency: 28.9%

Maximum Frequency of an Element After Performing Operations I

Array Binary Search Sliding Window Sorting Prefix Sum

#67

Rank

#3647MediumFrequency: 28.1%

Zero Array Transformation III

Array Two Pointers Greedy Sorting Heap (Priority Queue)Prefix Sum

#68

Rank

#914MediumFrequency: 27.8%

Random Point in Non-overlapping Rectangles

Array Math Binary Search Reservoir Sampling Prefix Sum Ordered Set Randomized

#69

Rank

#2135HardFrequency: 27.7%

Maximum Number of Ways to Partition an Array

Array Hash Table Counting Enumeration Prefix Sum

#70

Rank

#519MediumFrequency: 27.3%

Widest Pair of Indices With Equal Range Sum

#71

Rank

#1473MediumFrequency: 27.3%

Find the Longest Substring Containing Vowels in Even Counts

#72

Rank

#2142MediumFrequency: 27.3%

Average Height of Buildings in Each Segment

Array Sorting Heap (Priority Queue)Prefix Sum

#73

Rank

#2471MediumFrequency: 27.3%

Minimum Amount of Time to Collect Garbage

#74

Rank

#3492MediumFrequency: 27.3%

Count Submatrices With Equal Frequency of X and Y

#75

Rank

#1514EasyFrequency: 27.3%

Minimum Value to Get Positive Step by Step Sum

#76

Rank

#4083MediumFrequency: 27.3%

Stable Subarrays With Equal Boundary and Interior Sum

#77

Rank

#1776MediumFrequency: 27.2%

Minimum Operations to Reduce X to Zero

Array Hash Table Binary Search Sliding Window Prefix Sum

#78

Rank

#2325MediumFrequency: 26.5%

Number of Ways to Select Buildings

#79

Rank

#2358MediumFrequency: 26.5%

Number of Ways to Split Array

#80

Rank

#2449HardFrequency: 26.5%

Maximum Number of Robots Within Budget

Array Binary Search Queue Sliding Window Heap (Priority Queue)Prefix Sum Monotonic Queue

#81

Rank

#2530MediumFrequency: 25.3%

Minimize Maximum of Array

Array Binary Search Dynamic Programming Greedy Prefix Sum

#82

Rank

#3211HardFrequency: 24.6%

Find Maximum Non-decreasing Array Length

Array Binary Search Dynamic Programming Stack Queue Monotonic Stack Prefix Sum Monotonic Queue

#83

Rank

#1242MediumFrequency: 24.4%

Matrix Block Sum

#84

Rank

#1413MediumFrequency: 24.4%

Maximum Side Length of a Square with Sum Less than or Equal to Threshold

Array Binary Search Matrix Prefix Sum

#85

Rank

#2055MediumFrequency: 24.4%

Describe the Painting

Array Hash Table Sorting Prefix Sum

#86

Rank

#3640HardFrequency: 24.4%

Maximum Frequency of an Element After Performing Operations II

Array Binary Search Sliding Window Sorting Prefix Sum

#87

Rank

#1042HardFrequency: 23.6%

Minimum Cost to Merge Stones

#88

Rank

#2309MediumFrequency: 23.6%

Maximize Number of Subsequences in a String

String Greedy Prefix Sum

#89

Rank

#2342MediumFrequency: 23.6%

Minimum Average Difference

#90

Rank

#3210MediumFrequency: 23.6%

Count Beautiful Substrings I

Hash Table Math String Enumeration Number Theory Prefix Sum

#91

Rank

#3955HardFrequency: 23.4%

Threshold Majority Queries

Array Hash Table Binary Search Divide and Conquer Counting Prefix Sum

#92

Rank

#2145MediumFrequency: 22.5%

Grid Game

#93

Rank

#878MediumFrequency: 22.5%

Shifting Letters

#94

Rank

#363HardFrequency: 22.1%

Max Sum of Rectangle No Larger Than K

Array Binary Search Matrix Prefix Sum Ordered Set

#95

Rank

#1555HardFrequency: 22.1%

Number of Ways of Cutting a Pizza

Array Dynamic Programming Memoization Matrix Prefix Sum

#96

Rank

#1632MediumFrequency: 22.1%

Number of Good Ways to Split a String

Hash Table String Dynamic Programming Bit Manipulation Prefix Sum

#97

Rank

#2001MediumFrequency: 22.1%

Jump Game VII

String Dynamic Programming Sliding Window Prefix Sum

#98

Rank

#1206MediumFrequency: 22.1%

Corporate Flight Bookings

#99

Rank

#4047HardFrequency: 22.1%

Longest Balanced Subarray II

Array Hash Table Divide and Conquer Segment Tree Prefix Sum

#100

Rank

#2205MediumFrequency: 21.9%

Find Good Days to Rob the Bank

#101

Rank

#2465MediumFrequency: 21.5%

Shifting Letters II

#102

Rank

#4240MediumFrequency: 21.5%

Find the Smallest Balanced Index

#103

Rank

#2394HardFrequency: 20.9%

Count Subarrays With Score Less Than K

#104

Rank

#3794MediumFrequency: 20.9%

Find the Minimum Amount of Time to Brew Potions

#105

Rank

#2714EasyFrequency: 20.9%

Left and Right Sum Differences

#106

Rank

#1990MediumFrequency: 20.3%

Get Biggest Three Rhombus Sums in a Grid

Array Math Sorting Heap (Priority Queue)Matrix Prefix Sum

#107

Rank

#2469EasyFrequency: 20.3%

Longest Subsequence With Limited Sum

#108

Rank

#2044MediumFrequency: 20.3%

Number of Wonderful Substrings

#109

Rank

#1145HardFrequency: 20%

Number of Submatrices That Sum to Target

Array Hash Table Matrix Prefix Sum

#110

Rank

#1240MediumFrequency: 20%

Stone Game II

Array Math Dynamic Programming Minimax Prefix Sum Game Theory Zero-Sum Game

#111

Rank

#1725MediumFrequency: 20%

Number of Sets of K Non-Overlapping Line Segments

Math Dynamic Programming Combinatorics Prefix Sum

#112

Rank

#1937HardFrequency: 20%

Maximize the Beauty of the Garden

#113

Rank

#2018HardFrequency: 20%

Minimum Space Wasted From Packaging

#114

Rank

#2369MediumFrequency: 20%

Maximum Sum Score of Array

#115

Rank

#2571EasyFrequency: 20%

Find the Pivot Integer

Math Prefix Sum

#116

Rank

#3208HardFrequency: 20%

Count Beautiful Substrings II

Hash Table Math String Number Theory Prefix Sum

#117

Rank

#4192HardFrequency: 20%

Minimum Cost to Partition a Binary String

String Divide and Conquer Prefix Sum

#118

Rank

#370MediumFrequency: 19.5%

Range Addition

#119

Rank

#732HardFrequency: 19.5%

My Calendar III

Binary Search Design Segment Tree Prefix Sum Ordered Set

#120

Rank

#831MediumFrequency: 19.5%

Largest Sum of Averages

#121

Rank

#3311EasyFrequency: 19.5%

Ant on the Boundary

#122

Rank

#3535HardFrequency: 19.5%

Find the Count of Monotonic Pairs I

Array Math Dynamic Programming Combinatorics Prefix Sum

#123

Rank

#3761HardFrequency: 19.5%

Maximum Difference Between Even and Odd Frequency II

String Sliding Window Enumeration Prefix Sum

#124

Rank

#1793MediumFrequency: 19.5%

Minimum Moves to Make Array Complementary

#125

Rank

#4074MediumFrequency: 19.5%

Count Subarrays With Majority Element I

Array Hash Table Divide and Conquer Segment Tree Merge Sort Counting Prefix Sum

#126

Rank

#1393HardFrequency: 18%

Maximum Value of K Coins From Piles

#127

Rank

#1615MediumFrequency: 18%

Range Sum of Sorted Subarray Sums

Array Two Pointers Binary Search Sorting Prefix Sum

#128

Rank

#1860MediumFrequency: 18%

Find Kth Largest XOR Coordinate Value

Array Divide and Conquer Bit Manipulation Sorting Heap (Priority Queue)Matrix Prefix Sum Quickselect

#129

Rank

#2569HardFrequency: 18%

Number of Beautiful Partitions

#130

Rank

#2625MediumFrequency: 18%

Increment Submatrices by One

#131

Rank

#3152MediumFrequency: 18%

Maximum Value of an Ordered Triplet II

#132

Rank

#3618HardFrequency: 18%

Find the Original Typed String II

#133

Rank

#2529MediumFrequency: 18%

Range Product Queries of Powers

#134

Rank

#4015MediumFrequency: 18%

Split Array With Minimum Difference

#135

Rank

#3962HardFrequency: 18%

Number of ZigZag Arrays I

#136

Rank

#644HardFrequency: 16.4%

Maximum Average Subarray II

#137

Rank

#1649MediumFrequency: 16.4%

Maximum Number of Non-Overlapping Subarrays With Sum Equals Target

#138

Rank

#1859MediumFrequency: 16.4%

Change Minimum Characters to Satisfy One of Three Conditions

Hash Table String Counting Prefix Sum

#139

Rank

#2034MediumFrequency: 16.4%

Minimum Absolute Difference Queries

#140

Rank

#2311HardFrequency: 16.4%

Minimum White Tiles After Covering With Carpets

#141

Rank

#2359MediumFrequency: 16.4%

Maximum White Tiles Covered by a Carpet

Array Binary Search Greedy Sliding Window Sorting Prefix Sum

#142

Rank

#2385MediumFrequency: 16.4%

Count Positions on Street With Required Brightness

#143

Rank

#1037HardFrequency: 16.4%

Minimum Number of K Consecutive Bit Flips

Array Bit Manipulation Queue Sliding Window Prefix Sum Brute-Force Search

#144

Rank

#3583HardFrequency: 16.4%

Sorted GCD Pair Queries

Array Hash Table Math Binary Search Combinatorics Counting Number Theory Prefix Sum Euclidean Algorithm Greatest Common Divisor

#145

Rank

#4136MediumFrequency: 16.4%

Concatenate Non-Zero Digits and Multiply by Sum II

Math String Prefix Sum

#146

Rank

#1631MediumFrequency: 16.1%

Number of Sub-arrays With Odd Sum

Array Math Dynamic Programming Prefix Sum

#147

Rank

#1787MediumFrequency: 15.7%

Sum of Absolute Differences in a Sorted Array

#148

Rank

#3653MediumFrequency: 15.7%

Maximum Subarray Sum With Length Divisible by K

#149

Rank

#2576MediumFrequency: 15.7%

Minimum Penalty for a Shop

#150

Rank

#1435MediumFrequency: 14.6%

XOR Queries of a Subarray

#151

Rank

#3406MediumFrequency: 14.6%

Find All Possible Stable Binary Arrays I

#152

Rank

#3383MediumFrequency: 13.2%

Taking Maximum Energy From the Mystic Dungeon

#153

Rank

#4045MediumFrequency: 13.2%

Longest Balanced Subarray I

Array Hash Table Divide and Conquer Segment Tree Prefix Sum

#154

Rank

#4056MediumFrequency: 13.2%

Longest Balanced Substring II

#155

Rank

#2229HardFrequency: 12.6%

Maximum Fruits Harvested After at Most K Steps

#156

Rank

#3470HardFrequency: 12.6%

Maximum Score From Grid Operations

#157

Rank

#3427MediumFrequency: 12%

Special Array II

#158

Rank

#3031MediumFrequency: 12%

Construct Product Matrix

#159

Rank

#3849MediumFrequency: 12%

Equal Sum Grid Partition I

Array Matrix Enumeration Prefix Sum

#160

Rank

#1321MediumFrequency: 12%

Get Equal Substrings Within Budget

#161

Rank

#3835MediumFrequency: 11.4%

Count Partitions With Max-Min Difference at Most K

Array Dynamic Programming Queue Sliding Window Prefix Sum Monotonic Queue

#162

Rank

#2134MediumFrequency: 10.5%

Maximize the Confusion of an Exam

#163

Rank

#2488MediumFrequency: 10.5%

Divide Intervals Into Minimum Number of Groups

Array Two Pointers Greedy Sorting Heap (Priority Queue)Prefix Sum

#164

Rank

#3688HardFrequency: 10.5%

Maximize Subarray Sum After Removing All Occurrences of One Element

Array Hash Table Divide and Conquer Dynamic Programming Segment Tree Prefix Sum

#165

Rank

#2721MediumFrequency: 10.5%

Sum of Distances

#166

Rank

#2618HardFrequency: 10.5%

Maximize the Minimum Powered City

Array Binary Search Greedy Queue Sliding Window Prefix Sum

#167

Rank

#2718MediumFrequency: 10.3%

Minimum Operations to Make All Array Elements Equal

#168

Rank

#2655MediumFrequency: 10.3%

Rearrange Array to Maximize Prefix Score

#169

Rank

#2878MediumFrequency: 10.3%

Apply Operations to Make All Array Elements Equal to Zero

#170

Rank

#2102EasyFrequency: 10.3%

Find the Middle Index in Array

#171

Rank

#3616EasyFrequency: 10.3%

Make Array Elements Equal to Zero

#172

Rank

#1311MediumFrequency: 10.3%

Largest Magic Square

#173

Rank

#2006MediumFrequency: 8.1%

Find the Student that Will Replace the Chalk

Array Binary Search Simulation Prefix Sum

#174

Rank

#2915MediumFrequency: 8.1%

Count of Interesting Subarrays

#175

Rank

#3704EasyFrequency: 8.1%

Count Partitions with Even Sum Difference

#176

Rank

#3338MediumFrequency: 8.1%

Count Submatrices with Top-Left Element and Sum Less Than k

#177

Rank

#3850HardFrequency: 8.1%

Equal Sum Grid Partition II

Array Hash Table Matrix Enumeration Prefix Sum

#178

Rank

#3731EasyFrequency: 8.1%

Sum of Variable Length Subarrays

#179

Rank

#4153HardFrequency: 7.3%

Count Routes to Climb a Rectangular Grid

#180

Rank

#4075HardFrequency: 7.3%

Count Subarrays With Majority Element II

Array Hash Table Divide and Conquer Segment Tree Merge Sort Prefix Sum

#181

Rank

#4318MediumFrequency: 7.3%

Valid Subarrays With Matching Sum Digits I

Array Hash Table Sliding Window Enumeration Prefix Sum

#182

Rank

#3154EasyFrequency: 7.3%

Maximum Value of an Ordered Triplet I

#183

Rank

#2005EasyFrequency: 7.2%

Check if All the Integers in a Range Are Covered

#184

Rank

#3407HardFrequency: 7.2%

Find All Possible Stable Binary Arrays II

#185

Rank

#1535HardFrequency: 5.5%

Build Array Where You Can Find The Maximum Exactly K Comparisons

#186

Rank

#1831MediumFrequency: 5.5%

Ways to Split Array Into Three Subarrays

#187

Rank

#3798HardFrequency: 5.5%

Longest Special Path II

Array Hash Table Tree Depth-First Search Prefix Sum

#188

Rank

#3196HardFrequency: 5.5%

Apply Operations to Maximize Frequency Score

Array Binary Search Sliding Window Sorting Prefix Sum

#189

Rank

#814HardFrequency: 5.5%

Smallest Rotation with Highest Score

#190

Rank

#1553MediumFrequency: 5%

Count Triplets That Can Form Two Arrays of Equal XOR

Array Hash Table Math Bit Manipulation Prefix Sum

#191

Rank

#3247MediumFrequency: 5%

Number of Same-End Substrings

Array Hash Table String Counting Prefix Sum

#192

Rank

#2787MediumFrequency: 5%

Movement of Robots

Array Brainteaser Sorting Prefix Sum

#193

Rank

#3833HardFrequency: 5%

Merge Operations for Minimum Travel Time

#194

Rank

#3591MediumFrequency: 5%

Shift Distance Between Two Strings

#195

Rank

#3913MediumFrequency: 5%

Partition Array to Minimize XOR

Array Dynamic Programming Bit Manipulation Prefix Sum

#196

Rank

#4265MediumFrequency: 5%

Longest Balanced Substring After One Swap

#197

Rank

#3313HardFrequency: 5%

Maximum Strength of K Disjoint Subarrays

#198

Rank

#4059MediumFrequency: 5%

Design Exam Scores Tracker

Array Binary Search Design Prefix Sum

#199

Rank

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Prefix Sum Interview Questions

Master 199 prefix sum problems frequently asked in technical interviews. These questions test your understanding of prefix sumconcepts and are essential for coding interview success.

199

Total Problems

Easy

126

Medium

Hard

Maximum Points You Can Obtain from Cards

Rank

#912MediumFrequency: 87.7%

Random Pick with Weight

Array Math Binary Search Prefix Sum Randomized

Rank

#560MediumFrequency: 87.2%

Subarray Sum Equals K

Rank

#253MediumFrequency: 83.8%

Meeting Rooms II

Array Two Pointers Greedy Sorting Heap (Priority Queue)Prefix Sum

Rank

#1046MediumFrequency: 83.2%

Max Consecutive Ones III

Rank

#2691MediumFrequency: 80.7%

Count Vowel Strings in Ranges

Rank

#238MediumFrequency: 76%

Product of Array Except Self

Rank

#1695MediumFrequency: 73.2%

Maximum Sum Obtained of Any Permutation

Rank

#713MediumFrequency: 66.4%

Subarray Product Less Than K

Rank

#2002HardFrequency: 65.2%

Stone Game VIII

Array Math Dynamic Programming Minimax Prefix Sum Game Theory Zero-Sum Game

#10

Rank

#1219MediumFrequency: 62.5%

Longest Well-Performing Interval

Array Hash Table Stack Monotonic Stack Prefix Sum

#11

Rank

#2466HardFrequency: 62.5%

Maximum Segment Sum After Removals

Array Union-Find Prefix Sum Ordered Set

#12

Rank

#3974MediumFrequency: 62.5%

XOR After Range Multiplication Queries I

Array Divide and Conquer Simulation Prefix Sum

#13

Rank

#3975HardFrequency: 62.5%

XOR After Range Multiplication Queries II

Array Divide and Conquer Prefix Sum

#14

Rank

#523MediumFrequency: 59.8%

Continuous Subarray Sum

Array Hash Table Math Prefix Sum Pigeonhole Principle

#15

Rank

#3880MediumFrequency: 59.6%

Minimum Time to Visit All Houses

#16

Rank

#2249MediumFrequency: 59.3%

Count the Hidden Sequences

#17

Rank

#410HardFrequency: 57.6%

Split Array Largest Sum

Array Binary Search Dynamic Programming Greedy Prefix Sum

#18

Rank

#1016MediumFrequency: 57%

Subarray Sums Divisible by K

#19

Rank

#3789HardFrequency: 55%

Maximize Subarrays After Removing One Conflicting Pair

Array Segment Tree Enumeration Prefix Sum

#20

Rank

#2676MediumFrequency: 54.4%

Find the Score of All Prefixes of an Array

#21

Rank

#3327HardFrequency: 54.4%

Minimum Moves to Pick K Ones

#22

Rank

#525MediumFrequency: 53.4%

Contiguous Array

#23

Rank

#3271MediumFrequency: 53.4%

Count the Number of Houses at a Certain Distance I

Breadth-First Search Graph Theory Prefix Sum

#24

Rank

#3310HardFrequency: 53.4%

Count the Number of Houses at a Certain Distance II

Graph Theory Prefix Sum

#25

Rank

#2574HardFrequency: 52.4%

Count Subarrays With Median K

#26

Rank

#303EasyFrequency: 51.8%

Range Sum Query - Immutable

Array Design Prefix Sum

#27

Rank

#1966MediumFrequency: 51.8%

Frequency of the Most Frequent Element

Array Binary Search Greedy Sliding Window Sorting Prefix Sum

#28

Rank

#209MediumFrequency: 51.4%

Minimum Size Subarray Sum

#29

Rank

#2075MediumFrequency: 51.4%

Brightest Position on Street

Array Sorting Prefix Sum Ordered Set

#30

Rank

#1985MediumFrequency: 49.9%

Maximum Subarray Min-Product

Array Stack Monotonic Stack Prefix Sum Cartesian Tree

#31

Rank

#3034EasyFrequency: 49.9%

Points That Intersect With Cars

#32

Rank

#3751MediumFrequency: 48.9%

Maximum Frequency After Subarray Operation

Array Hash Table Dynamic Programming Greedy Enumeration Prefix Sum

#33

Rank

#2165MediumFrequency: 47.7%

Plates Between Candles

Array String Binary Search Prefix Sum

#34

Rank

#1940MediumFrequency: 47.5%

Maximum XOR for Each Query

#35

Rank

#3475MediumFrequency: 47.5%

Minimum Operations to Make Binary Array Elements Equal to One I

Array Bit Manipulation Queue Sliding Window Prefix Sum

#36

Rank

#3980MediumFrequency: 47.5%

Best Time to Buy and Sell Stock using Strategy

#37

Rank

#3715MediumFrequency: 47.3%

Maximum Coins From K Consecutive Bags

Array Binary Search Greedy Sliding Window Sorting Prefix Sum

#38

Rank

#1603EasyFrequency: 47%

Running Sum of 1d Array

#39

Rank

#3639MediumFrequency: 46.7%

Zero Array Transformation I

#40

Rank

#1693EasyFrequency: 44.7%

Sum of All Odd Length Subarrays

#41

Rank

#4149MediumFrequency: 44.7%

Minimum Increase to Maximize Special Indices

Array Dynamic Programming Greedy Prefix Sum

#42

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#1370MediumFrequency: 44%

Count Number of Nice Subarrays

Array Hash Table Math Sliding Window Prefix Sum

#43

Rank

#1184MediumFrequency: 43.2%

Car Pooling

Array Sorting Heap (Priority Queue)Simulation Prefix Sum

#44

Rank

#2334HardFrequency: 43%

Number of Flowers in Full Bloom

Asked at Databricks

Array Hash Table Binary Search Sorting Prefix Sum Ordered Set

#45

Rank

#724EasyFrequency: 42%

Find Pivot Index

#46

Rank

#2368HardFrequency: 40.2%

Sum of Total Strength of Wizards

Array Stack Monotonic Stack Prefix Sum

#47

Rank

#1783MediumFrequency: 39.2%

Ways to Make a Fair Array

Asked at DoorDash

#48

Rank

#3643MediumFrequency: 39%

Zero Array Transformation II

#49

Rank

#689HardFrequency: 36.8%

Maximum Sum of 3 Non-Overlapping Subarrays

Array Dynamic Programming Sliding Window Prefix Sum

#50

Rank

#966MediumFrequency: 36.3%

Binary Subarrays With Sum

Array Hash Table Sliding Window Prefix Sum

#51

Rank

#1983EasyFrequency: 35.7%

Maximum Population Year

Array Counting Prefix Sum

#52

Rank

#325MediumFrequency: 35%

Maximum Size Subarray Sum Equals k

#53

Rank

#2538HardFrequency: 33.3%

Minimum Cost to Make Array Equal

#54

Rank

#1477MediumFrequency: 33%

Product of the Last K Numbers

Array Math Design Data Stream Prefix Sum

#55

Rank

#1895MediumFrequency: 31.8%

Minimum Number of Operations to Move All Balls to Each Box

#56

Rank

#3265MediumFrequency: 31.8%

Maximum Good Subarray Sum

#57

Rank

#2730MediumFrequency: 31.3%

Maximum OR

Array Greedy Bit Manipulation Prefix Sum

#58

Rank

#1805HardFrequency: 31.1%

Minimum Adjacent Swaps for K Consecutive Ones

#59

Rank

#1833EasyFrequency: 30.4%

Find the Highest Altitude

#60

Rank

#304MediumFrequency: 30.4%

Range Sum Query 2D - Immutable

Array Design Matrix Prefix Sum

#61

Rank

#1694MediumFrequency: 30.2%

Make Sum Divisible by P

#62

Rank

#1537EasyFrequency: 29.7%

Maximum Score After Splitting a String

#63

Rank

#2059MediumFrequency: 29.7%

Unique Length-3 Palindromic Subsequences

Array Binary Search Design Segment Tree Prefix Sum Ordered Set

#64

Rank

#731MediumFrequency: 29.5%

My Calendar II

Asked at Apple

#65

Rank

#892HardFrequency: 29.1%

Shortest Subarray with Sum at Least K

Array Binary Search Queue Sliding Window Heap (Priority Queue)Prefix Sum Monotonic Queue

#66

Rank

#3622MediumFrequency: 28.9%

Maximum Frequency of an Element After Performing Operations I

Array Binary Search Sliding Window Sorting Prefix Sum

#67

Rank

#3647MediumFrequency: 28.1%

Zero Array Transformation III

Array Two Pointers Greedy Sorting Heap (Priority Queue)Prefix Sum

#68

Rank

#914MediumFrequency: 27.8%

Random Point in Non-overlapping Rectangles

Array Math Binary Search Reservoir Sampling Prefix Sum Ordered Set Randomized

#69

Rank

#2135HardFrequency: 27.7%

Maximum Number of Ways to Partition an Array

Array Hash Table Counting Enumeration Prefix Sum

#70

Rank

#519MediumFrequency: 27.3%

Widest Pair of Indices With Equal Range Sum

#71

Rank

#1473MediumFrequency: 27.3%

Find the Longest Substring Containing Vowels in Even Counts

#72

Rank

#2142MediumFrequency: 27.3%

Average Height of Buildings in Each Segment

Array Sorting Heap (Priority Queue)Prefix Sum

#73

Rank

#2471MediumFrequency: 27.3%

Minimum Amount of Time to Collect Garbage

#74

Rank

#3492MediumFrequency: 27.3%

Count Submatrices With Equal Frequency of X and Y

#75

Rank

#1514EasyFrequency: 27.3%

Minimum Value to Get Positive Step by Step Sum

#76

Rank

#4083MediumFrequency: 27.3%

Stable Subarrays With Equal Boundary and Interior Sum

#77

Rank

#1776MediumFrequency: 27.2%

Minimum Operations to Reduce X to Zero

Array Hash Table Binary Search Sliding Window Prefix Sum

#78

Rank

#2325MediumFrequency: 26.5%

Number of Ways to Select Buildings

#79

Rank

#2358MediumFrequency: 26.5%

Number of Ways to Split Array

#80

Rank

#2449HardFrequency: 26.5%

Maximum Number of Robots Within Budget

Array Binary Search Queue Sliding Window Heap (Priority Queue)Prefix Sum Monotonic Queue

#81

Rank

#2530MediumFrequency: 25.3%

Minimize Maximum of Array

Array Binary Search Dynamic Programming Greedy Prefix Sum

#82

Rank

#3211HardFrequency: 24.6%

Find Maximum Non-decreasing Array Length

Array Binary Search Dynamic Programming Stack Queue Monotonic Stack Prefix Sum Monotonic Queue

#83

Rank

#1242MediumFrequency: 24.4%

Matrix Block Sum

#84

Rank

#1413MediumFrequency: 24.4%

Maximum Side Length of a Square with Sum Less than or Equal to Threshold

Array Binary Search Matrix Prefix Sum

#85

Rank

#2055MediumFrequency: 24.4%

Describe the Painting

Array Hash Table Sorting Prefix Sum

#86

Rank

#3640HardFrequency: 24.4%

Maximum Frequency of an Element After Performing Operations II

Array Binary Search Sliding Window Sorting Prefix Sum

#87

Rank

#1042HardFrequency: 23.6%

Minimum Cost to Merge Stones

#88

Rank

#2309MediumFrequency: 23.6%

Maximize Number of Subsequences in a String

String Greedy Prefix Sum

#89

Rank

#2342MediumFrequency: 23.6%

Minimum Average Difference

#90

Rank

#3210MediumFrequency: 23.6%

Count Beautiful Substrings I

Hash Table Math String Enumeration Number Theory Prefix Sum

#91

Rank

#3955HardFrequency: 23.4%

Threshold Majority Queries

Array Hash Table Binary Search Divide and Conquer Counting Prefix Sum

#92

Rank

#2145MediumFrequency: 22.5%

Grid Game

#93

Rank

#878MediumFrequency: 22.5%

Shifting Letters

#94

Rank

#363HardFrequency: 22.1%

Max Sum of Rectangle No Larger Than K

Array Binary Search Matrix Prefix Sum Ordered Set

#95

Rank

#1555HardFrequency: 22.1%

Number of Ways of Cutting a Pizza

Array Dynamic Programming Memoization Matrix Prefix Sum

#96

Rank

#1632MediumFrequency: 22.1%

Number of Good Ways to Split a String

Hash Table String Dynamic Programming Bit Manipulation Prefix Sum

#97

Rank

#2001MediumFrequency: 22.1%

Jump Game VII

String Dynamic Programming Sliding Window Prefix Sum

#98

Rank

#1206MediumFrequency: 22.1%

Corporate Flight Bookings

#99

Rank

#4047HardFrequency: 22.1%

Longest Balanced Subarray II

Array Hash Table Divide and Conquer Segment Tree Prefix Sum

#100

Rank

#2205MediumFrequency: 21.9%

Find Good Days to Rob the Bank

#101

Rank

#2465MediumFrequency: 21.5%

Shifting Letters II

#102

Rank

#4240MediumFrequency: 21.5%

Find the Smallest Balanced Index

#103

Rank

#2394HardFrequency: 20.9%

Count Subarrays With Score Less Than K

#104

Rank

#3794MediumFrequency: 20.9%

Find the Minimum Amount of Time to Brew Potions

#105

Rank

#2714EasyFrequency: 20.9%

Left and Right Sum Differences

#106

Rank

#1990MediumFrequency: 20.3%

Get Biggest Three Rhombus Sums in a Grid

Array Math Sorting Heap (Priority Queue)Matrix Prefix Sum

#107

Rank

#2469EasyFrequency: 20.3%

Longest Subsequence With Limited Sum

#108

Rank

#2044MediumFrequency: 20.3%

Number of Wonderful Substrings

#109

Rank

#1145HardFrequency: 20%

Number of Submatrices That Sum to Target

Array Hash Table Matrix Prefix Sum

#110

Rank

#1240MediumFrequency: 20%

Stone Game II

Array Math Dynamic Programming Minimax Prefix Sum Game Theory Zero-Sum Game

#111

Rank

#1725MediumFrequency: 20%

Number of Sets of K Non-Overlapping Line Segments

Math Dynamic Programming Combinatorics Prefix Sum

#112

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#1937HardFrequency: 20%

Maximize the Beauty of the Garden

#113

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#2018HardFrequency: 20%

Minimum Space Wasted From Packaging

#114

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#2369MediumFrequency: 20%

Maximum Sum Score of Array

#115

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#2571EasyFrequency: 20%

Find the Pivot Integer

Math Prefix Sum

#116

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#3208HardFrequency: 20%

Count Beautiful Substrings II

Hash Table Math String Number Theory Prefix Sum

#117

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#4192HardFrequency: 20%

Minimum Cost to Partition a Binary String

String Divide and Conquer Prefix Sum

#118

Rank

#370MediumFrequency: 19.5%

Range Addition

#119

Rank

#732HardFrequency: 19.5%

My Calendar III

Binary Search Design Segment Tree Prefix Sum Ordered Set

#120

Rank

#831MediumFrequency: 19.5%

Largest Sum of Averages

#121

Rank

#3311EasyFrequency: 19.5%

Ant on the Boundary

#122

Rank

#3535HardFrequency: 19.5%

Find the Count of Monotonic Pairs I

Array Math Dynamic Programming Combinatorics Prefix Sum

#123

Rank

#3761HardFrequency: 19.5%

Maximum Difference Between Even and Odd Frequency II

String Sliding Window Enumeration Prefix Sum

#124

Rank

#1793MediumFrequency: 19.5%

Minimum Moves to Make Array Complementary

#125

Rank

#4074MediumFrequency: 19.5%

Count Subarrays With Majority Element I

Array Hash Table Divide and Conquer Segment Tree Merge Sort Counting Prefix Sum

#126

Rank

#1393HardFrequency: 18%

Maximum Value of K Coins From Piles

#127

Rank

#1615MediumFrequency: 18%

Range Sum of Sorted Subarray Sums

Array Two Pointers Binary Search Sorting Prefix Sum

#128

Rank

#1860MediumFrequency: 18%

Find Kth Largest XOR Coordinate Value

Array Divide and Conquer Bit Manipulation Sorting Heap (Priority Queue)Matrix Prefix Sum Quickselect

#129

Rank

#2569HardFrequency: 18%

Number of Beautiful Partitions

#130

Rank

#2625MediumFrequency: 18%

Increment Submatrices by One

#131

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#3152MediumFrequency: 18%

Maximum Value of an Ordered Triplet II

#132

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#3618HardFrequency: 18%

Find the Original Typed String II

#133

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#2529MediumFrequency: 18%

Range Product Queries of Powers

#134

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#4015MediumFrequency: 18%

Split Array With Minimum Difference

#135

Rank

#3962HardFrequency: 18%

Number of ZigZag Arrays I

#136

Rank

#644HardFrequency: 16.4%

Maximum Average Subarray II

#137

Rank

#1649MediumFrequency: 16.4%

Maximum Number of Non-Overlapping Subarrays With Sum Equals Target

#138

Rank

#1859MediumFrequency: 16.4%

Change Minimum Characters to Satisfy One of Three Conditions

Hash Table String Counting Prefix Sum

#139

Rank

#2034MediumFrequency: 16.4%

Minimum Absolute Difference Queries

#140

Rank

#2311HardFrequency: 16.4%

Minimum White Tiles After Covering With Carpets

#141

Rank

#2359MediumFrequency: 16.4%

Maximum White Tiles Covered by a Carpet

Array Binary Search Greedy Sliding Window Sorting Prefix Sum

#142

Rank

#2385MediumFrequency: 16.4%

Count Positions on Street With Required Brightness

#143

Rank

#1037HardFrequency: 16.4%

Minimum Number of K Consecutive Bit Flips

Array Bit Manipulation Queue Sliding Window Prefix Sum Brute-Force Search

#144

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#3583HardFrequency: 16.4%

Sorted GCD Pair Queries

Array Hash Table Math Binary Search Combinatorics Counting Number Theory Prefix Sum Euclidean Algorithm Greatest Common Divisor

#145

Rank

#4136MediumFrequency: 16.4%

Concatenate Non-Zero Digits and Multiply by Sum II

Math String Prefix Sum

#146

Rank

#1631MediumFrequency: 16.1%

Number of Sub-arrays With Odd Sum

Array Math Dynamic Programming Prefix Sum

#147

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#1787MediumFrequency: 15.7%

Sum of Absolute Differences in a Sorted Array

#148

Rank

#3653MediumFrequency: 15.7%

Maximum Subarray Sum With Length Divisible by K

#149

Rank

#2576MediumFrequency: 15.7%

Minimum Penalty for a Shop

#150

Rank

#1435MediumFrequency: 14.6%

XOR Queries of a Subarray

#151

Rank

#3406MediumFrequency: 14.6%

Find All Possible Stable Binary Arrays I

#152

Rank

#3383MediumFrequency: 13.2%

Taking Maximum Energy From the Mystic Dungeon

#153

Rank

#4045MediumFrequency: 13.2%

Longest Balanced Subarray I

Array Hash Table Divide and Conquer Segment Tree Prefix Sum

#154

Rank

#4056MediumFrequency: 13.2%

Longest Balanced Substring II

#155

Rank

#2229HardFrequency: 12.6%

Maximum Fruits Harvested After at Most K Steps

#156

Rank

#3470HardFrequency: 12.6%

Maximum Score From Grid Operations

#157

Rank

#3427MediumFrequency: 12%

Special Array II

#158

Rank

#3031MediumFrequency: 12%

Construct Product Matrix

#159

Rank

#3849MediumFrequency: 12%

Equal Sum Grid Partition I

Array Matrix Enumeration Prefix Sum

#160

Rank

#1321MediumFrequency: 12%

Get Equal Substrings Within Budget

#161

Rank

#3835MediumFrequency: 11.4%

Count Partitions With Max-Min Difference at Most K

Array Dynamic Programming Queue Sliding Window Prefix Sum Monotonic Queue

#162

Rank

#2134MediumFrequency: 10.5%

Maximize the Confusion of an Exam

#163

Rank

#2488MediumFrequency: 10.5%

Divide Intervals Into Minimum Number of Groups

Array Two Pointers Greedy Sorting Heap (Priority Queue)Prefix Sum

#164

Rank

#3688HardFrequency: 10.5%

Maximize Subarray Sum After Removing All Occurrences of One Element

Array Hash Table Divide and Conquer Dynamic Programming Segment Tree Prefix Sum

#165

Rank

#2721MediumFrequency: 10.5%

Sum of Distances

#166

Rank

#2618HardFrequency: 10.5%

Maximize the Minimum Powered City

Array Binary Search Greedy Queue Sliding Window Prefix Sum

#167

Rank

#2718MediumFrequency: 10.3%

Minimum Operations to Make All Array Elements Equal

#168

Rank

#2655MediumFrequency: 10.3%

Rearrange Array to Maximize Prefix Score

#169

Rank

#2878MediumFrequency: 10.3%

Apply Operations to Make All Array Elements Equal to Zero

#170

Rank

#2102EasyFrequency: 10.3%

Find the Middle Index in Array

#171

Rank

#3616EasyFrequency: 10.3%

Make Array Elements Equal to Zero

#172

Rank

#1311MediumFrequency: 10.3%

Largest Magic Square

#173

Rank

#2006MediumFrequency: 8.1%

Find the Student that Will Replace the Chalk

Array Binary Search Simulation Prefix Sum

#174

Rank

#2915MediumFrequency: 8.1%

Count of Interesting Subarrays

#175

Rank

#3704EasyFrequency: 8.1%

Count Partitions with Even Sum Difference

#176

Rank

#3338MediumFrequency: 8.1%

Count Submatrices with Top-Left Element and Sum Less Than k

#177

Rank

#3850HardFrequency: 8.1%

Equal Sum Grid Partition II

Array Hash Table Matrix Enumeration Prefix Sum

#178

Rank

#3731EasyFrequency: 8.1%

Sum of Variable Length Subarrays

#179

Rank

#4153HardFrequency: 7.3%

Count Routes to Climb a Rectangular Grid

#180

Rank

#4075HardFrequency: 7.3%

Count Subarrays With Majority Element II

Array Hash Table Divide and Conquer Segment Tree Merge Sort Prefix Sum

#181

Rank

#4318MediumFrequency: 7.3%

Valid Subarrays With Matching Sum Digits I

Array Hash Table Sliding Window Enumeration Prefix Sum

#182

Rank

#3154EasyFrequency: 7.3%

Maximum Value of an Ordered Triplet I

#183

Rank

#2005EasyFrequency: 7.2%

Check if All the Integers in a Range Are Covered

#184

Rank

#3407HardFrequency: 7.2%

Find All Possible Stable Binary Arrays II

#185

Rank

#1535HardFrequency: 5.5%

Build Array Where You Can Find The Maximum Exactly K Comparisons

#186

Rank

#1831MediumFrequency: 5.5%

Ways to Split Array Into Three Subarrays

#187

Rank

#3798HardFrequency: 5.5%

Longest Special Path II

Array Hash Table Tree Depth-First Search Prefix Sum

#188

Rank

#3196HardFrequency: 5.5%

Apply Operations to Maximize Frequency Score

Array Binary Search Sliding Window Sorting Prefix Sum

#189

Rank

#814HardFrequency: 5.5%

Smallest Rotation with Highest Score

#190

Rank

#1553MediumFrequency: 5%

Count Triplets That Can Form Two Arrays of Equal XOR

Array Hash Table Math Bit Manipulation Prefix Sum

#191

Rank

#3247MediumFrequency: 5%

Number of Same-End Substrings

Array Hash Table String Counting Prefix Sum

#192

Rank

#2787MediumFrequency: 5%

Movement of Robots

Array Brainteaser Sorting Prefix Sum

#193

Rank

#3833HardFrequency: 5%

Merge Operations for Minimum Travel Time

#194

Rank

#3591MediumFrequency: 5%

Shift Distance Between Two Strings

#195

Rank

#3913MediumFrequency: 5%

Partition Array to Minimize XOR

Array Dynamic Programming Bit Manipulation Prefix Sum

#196

Rank

#4265MediumFrequency: 5%

Longest Balanced Substring After One Swap

#197

Rank

#3313HardFrequency: 5%

Maximum Strength of K Disjoint Subarrays

#198

Rank

#4059MediumFrequency: 5%

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