Counting Interview Questions

Rank

#347MediumFrequency: 81.3%

Top K Frequent Elements

Array Hash Table Divide and Conquer Sorting Heap (Priority Queue)Bucket Sort Counting Quickselect

Rank

#778MediumFrequency: 78.3%

Reorganize String

Hash Table String Greedy Sorting Heap (Priority Queue)Counting

Rank

#3994EasyFrequency: 76.6%

Find The Least Frequent Digit

Rank

#2301HardFrequency: 73.2%

Count Array Pairs Divisible by K

Array Hash Table Math Counting Number Theory Euclidean Algorithm Greatest Common Divisor

Rank

#2654EasyFrequency: 73.2%

Count the Number of Vowel Strings in Range

Array String Counting

Rank

#169EasyFrequency: 70.4%

Majority Element

Array Hash Table Divide and Conquer Sorting Counting Boyer–Moore Majority Vote Algorithm

Rank

#3778EasyFrequency: 69.8%

Transform Array by Parity

Rank

#3317MediumFrequency: 66.4%

Maximum Palindromes After Operations

Array Hash Table String Greedy Sorting Counting

Rank

#936MediumFrequency: 65.2%

RLE Iterator

Array Design Counting Iterator

#10

Rank

#1915EasyFrequency: 64.6%

Check if One String Swap Can Make Strings Equal

#11

Rank

#1469MediumFrequency: 63.5%

Minimum Number of Steps to Make Two Strings Anagram

#12

Rank

#621MediumFrequency: 63.1%

Task Scheduler

Array Hash Table Greedy Sorting Heap (Priority Queue)Counting

#13

Rank

#1055MediumFrequency: 62.2%

Pairs of Songs With Total Durations Divisible by 60

#14

Rank

#2237MediumFrequency: 61.1%

Longest Palindrome by Concatenating Two Letter Words

Array Hash Table String Greedy Counting

#15

Rank

#3736EasyFrequency: 60%

Find Valid Pair of Adjacent Digits in String

#16

Rank

#1341EasyFrequency: 59.6%

Split a String in Balanced Strings

#17

Rank

#3638HardFrequency: 59.3%

Minimum Operations to Make Character Frequencies Equal

Hash Table String Dynamic Programming Counting Enumeration

#18

Rank

#692MediumFrequency: 59.1%

Top K Frequent Words

Array Hash Table String Trie Sorting Heap (Priority Queue)Bucket Sort Counting

#19

Rank

#3594MediumFrequency: 58.8%

Identify the Largest Outlier in an Array

Array Hash Table Counting Enumeration

#20

Rank

#2594EasyFrequency: 55.8%

Count Pairs Of Similar Strings

#21

Rank

#387EasyFrequency: 55.2%

First Unique Character in a String

Hash Table String Queue Counting

#22

Rank

#2177EasyFrequency: 55.1%

Check Whether Two Strings are Almost Equivalent

#23

Rank

#383EasyFrequency: 55%

Ransom Note

#24

Rank

#982MediumFrequency: 50.3%

Minimum Increment to Make Array Unique

Array Greedy Sorting Counting

#25

Rank

#4253MediumFrequency: 49.9%

Minimum Cost to Equalize Arrays Using Swaps

#26

Rank

#2133MediumFrequency: 48.7%

Number of Pairs of Strings With Concatenation Equal to Target

#27

Rank

#1502MediumFrequency: 47.5%

Construct K Palindrome Strings

#28

Rank

#1643MediumFrequency: 47.5%

Number of Nodes in the Sub-Tree With the Same Label

Hash Table Tree Depth-First Search Breadth-First Search Counting DP on Trees

#29

Rank

#2331EasyFrequency: 47.5%

Intersection of Multiple Arrays

#30

Rank

#3335MediumFrequency: 47.5%

Minimum Operations to Write the Letter Y on a Grid

Array Hash Table Matrix Counting

#31

Rank

#1034HardFrequency: 46%

Subarrays with K Different Integers

#32

Rank

#451MediumFrequency: 43.2%

Sort Characters By Frequency

Hash Table String Sorting Heap (Priority Queue)Bucket Sort Counting

#33

Rank

#2270MediumFrequency: 43%

Find All Lonely Numbers in the Array

#34

Rank

#229MediumFrequency: 42.5%

Majority Element II

Array Hash Table Sorting Counting Boyer–Moore Majority Vote Algorithm

#35

Rank

#1708EasyFrequency: 41.4%

Design Parking System

Design Simulation Counting

#36

Rank

#3421EasyFrequency: 40.2%

Count Pairs That Form a Complete Day I

#37

Rank

#1510EasyFrequency: 35.7%

Find Lucky Integer in an Array

#38

Rank

#1983EasyFrequency: 35.7%

Maximum Population Year

Array Counting Prefix Sum

#39

Rank

#2308EasyFrequency: 34.3%

Divide Array Into Equal Pairs

#40

Rank

#1925MediumFrequency: 33.5%

Count Nice Pairs in an Array

#41

Rank

#3267MediumFrequency: 33.1%

Find Longest Special Substring That Occurs Thrice I

Hash Table String Binary Search Sliding Window Counting

#42

Rank

#1947HardFrequency: 31.3%

Number of Different Subsequences GCDs

Array Math Counting Number Theory Euclidean Algorithm Greatest Common Divisor

#43

Rank

#2139MediumFrequency: 31.1%

Detect Squares

Array Hash Table Design Counting Data Stream

#44

Rank

#1890MediumFrequency: 30.2%

Sum of Beauty of All Substrings

#45

Rank

#2433EasyFrequency: 29.5%

Best Poker Hand

#46

Rank

#2475MediumFrequency: 29.3%

Largest Palindromic Number

#47

Rank

#1227EasyFrequency: 29.1%

Number of Equivalent Domino Pairs

#48

Rank

#2289MediumFrequency: 29.1%

Minimum Operations to Make the Array Alternating

#49

Rank

#4061HardFrequency: 29.1%

Minimum Swaps to Avoid Forbidden Values

#50

Rank

#1635EasyFrequency: 28.9%

Number of Good Pairs

#51

Rank

#2378MediumFrequency: 28.1%

Sender With Largest Word Count

#52

Rank

#2135HardFrequency: 27.7%

Maximum Number of Ways to Partition an Array

Array Hash Table Counting Enumeration Prefix Sum

#53

Rank

#1604MediumFrequency: 27.7%

Least Number of Unique Integers after K Removals

#54

Rank

#1143MediumFrequency: 27.3%

Find Smallest Common Element in All Rows

Array Hash Table Binary Search Matrix Counting

#55

Rank

#594EasyFrequency: 27.2%

Longest Harmonious Subsequence

Array Hash Table Sliding Window Sorting Counting

#56

Rank

#1149EasyFrequency: 26.7%

Intersection of Three Sorted Arrays

Array Hash Table Binary Search Counting

#57

Rank

#1848EasyFrequency: 26.7%

Sum of Unique Elements

#58

Rank

#3707MediumFrequency: 26.7%

Find the Most Common Response

#59

Rank

#837EasyFrequency: 26.5%

Most Common Word

#60

Rank

#2116EasyFrequency: 26.5%

Count Number of Pairs With Absolute Difference K

#61

Rank

#2362MediumFrequency: 26.5%

Minimum Rounds to Complete All Tasks

#62

Rank

#3276MediumFrequency: 26.5%

Minimum Number of Pushes to Type Word II

#63

Rank

#1364MediumFrequency: 26.3%

Tuple with Same Product

#64

Rank

#2427EasyFrequency: 26.3%

First Letter to Appear Twice

Hash Table String Bit Manipulation Counting

#65

Rank

#1483MediumFrequency: 25.4%

Rank Teams by Votes

Array Hash Table String Sorting Counting

#66

Rank

#299MediumFrequency: 25.4%

Bulls and Cows

#67

Rank

#2448MediumFrequency: 25.4%

Count Number of Bad Pairs

#68

Rank

#1160MediumFrequency: 25.3%

Letter Tile Possibilities

Hash Table String Backtracking Counting

#69

Rank

#1381HardFrequency: 25.1%

Maximum Score Words Formed by Letters

Array Hash Table String Dynamic Programming Backtracking Bit Manipulation Counting Bitmask

#70

Rank

#1620MediumFrequency: 25.1%

Check If Array Pairs Are Divisible by k

#71

Rank

#3871EasyFrequency: 25.1%

Minimum Deletions for At Most K Distinct Characters

#72

Rank

#358HardFrequency: 24.6%

Rearrange String k Distance Apart

Hash Table String Greedy Sorting Heap (Priority Queue)Counting

#73

Rank

#950EasyFrequency: 24.4%

X of a Kind in a Deck of Cards

Array Hash Table Math Counting Number Theory Euclidean Algorithm Greatest Common Divisor

#74

Rank

#1396MediumFrequency: 24.4%

Count Servers that Communicate

Array Depth-First Search Breadth-First Search Union-Find Matrix Counting

#75

Rank

#1140MediumFrequency: 23.6%

Distant Barcodes

Array Hash Table Greedy Sorting Heap (Priority Queue)Counting

#76

Rank

#3094MediumFrequency: 23.6%

Minimum Number of Operations to Make Array Empty

#77

Rank

#3955HardFrequency: 23.4%

Threshold Majority Queries

Array Hash Table Binary Search Divide and Conquer Counting Prefix Sum

#78

Rank

#1777MediumFrequency: 22%

Determine if Two Strings Are Close

Hash Table String Sorting Counting

#79

Rank

#2405MediumFrequency: 21.9%

Minimum Number of Keypresses

#80

Rank

#3242EasyFrequency: 21.9%

Count Elements With Maximum Frequency

#81

Rank

#3354MediumFrequency: 21.9%

Replace Question Marks in String to Minimize Its Value

Hash Table String Greedy Sorting Heap (Priority Queue)Counting

#82

Rank

#2140HardFrequency: 21.5%

Longest Subsequence Repeated k Times

Hash Table Two Pointers String Backtracking Counting Enumeration

#83

Rank

#1986HardFrequency: 20.9%

Largest Color Value in a Directed Graph

Hash Table String Dynamic Programming Graph Theory Topological Sort Memoization Counting Directed Acyclic Graph

#84

Rank

#900MediumFrequency: 20.9%

Reordered Power of 2

Hash Table Math Sorting Counting Enumeration

#85

Rank

#3754MediumFrequency: 20.3%

Maximum Manhattan Distance After K Changes

Hash Table Math String Counting

#86

Rank

#1891HardFrequency: 20%

Count Pairs Of Nodes

Array Hash Table Two Pointers Binary Search Graph Theory Sorting Counting

#87

Rank

#2163EasyFrequency: 20%

Kth Distinct String in an Array

#88

Rank

#2372EasyFrequency: 20%

Rearrange Characters to Make Target String

#89

Rank

#2995MediumFrequency: 20%

Number of Unique Categories

Union-Find Interactive Counting

#90

Rank

#2312EasyFrequency: 19.5%

Most Frequent Number Following Key In an Array

#91

Rank

#2377EasyFrequency: 19.5%

Check if Number Has Equal Digit Count and Digit Value

#92

Rank

#2494HardFrequency: 19.5%

Sum of Prefix Scores of Strings

Array String Trie Counting

#93

Rank

#2525MediumFrequency: 19.5%

Count Number of Distinct Integers After Reverse Operations

#94

Rank

#829MediumFrequency: 19.5%

Subdomain Visit Count

#95

Rank

#4183MediumFrequency: 19.5%

Count Caesar Cipher Pairs

Array Hash Table Math String Counting

#96

Rank

#2300MediumFrequency: 19.5%

Construct String With Repeat Limit

Hash Table String Greedy Heap (Priority Queue)Counting

#97

Rank

#3753EasyFrequency: 19.5%

Maximum Difference Between Even and Odd Frequency I

#98

Rank

#1458EasyFrequency: 19.5%

Sort Integers by The Number of 1 Bits

Array Bit Manipulation Sorting Counting

#99

Rank

#4074MediumFrequency: 19.5%

Count Subarrays With Majority Element I

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

#100

Rank

#1758HardFrequency: 18%

Distribute Repeating Integers

Array Hash Table Dynamic Programming Backtracking Bit Manipulation Counting Bitmask

#101

Rank

#2615MediumFrequency: 18%

Make Number of Distinct Characters Equal

#102

Rank

#3266MediumFrequency: 18%

Find Longest Special Substring That Occurs Thrice II

Hash Table String Binary Search Sliding Window Counting

#103

Rank

#3384MediumFrequency: 18%

Minimum Number of Operations to Make Word K-Periodic

#104

Rank

#3416MediumFrequency: 18%

Sum of Digit Differences of All Pairs

#105

Rank

#3629MediumFrequency: 18%

Total Characters in String After Transformations I

Hash Table Math String Dynamic Programming Counting

#106

Rank

#4020MediumFrequency: 18%

Lexicographically Smallest Permutation Greater Than Target

Hash Table String Greedy Counting Enumeration

#107

Rank

#4055MediumFrequency: 18%

Longest Balanced Substring I

Hash Table String Counting Enumeration

#108

Rank

#1118HardFrequency: 16.4%

Divide Array Into Increasing Sequences

Array Counting

#109

Rank

#1169MediumFrequency: 16.4%

Largest Values From Labels

#110

Rank

#1750MediumFrequency: 16.4%

Check If Two Expression Trees are Equivalent

Hash Table Tree Depth-First Search Binary Tree Counting

#111

Rank

#1859MediumFrequency: 16.4%

Change Minimum Characters to Satisfy One of Three Conditions

Hash Table String Counting Prefix Sum

#112

Rank

#2071MediumFrequency: 16.4%

Longest Common Subsequence Between Sorted Arrays

#113

Rank

#3314MediumFrequency: 16.4%

Most Frequent Prime

Array Hash Table Math Matrix Counting Enumeration Number Theory Primality Test Sieve Theory Prime Number Sieve

#114

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

#115

Rank

#2174MediumFrequency: 16.4%

Next Greater Numerically Balanced Number

Hash Table Math Backtracking Counting Enumeration

#116

Rank

#2614EasyFrequency: 16.1%

Maximum Count of Positive Integer and Negative Integer

Array Binary Search Counting

#117

Rank

#1297EasyFrequency: 16.1%

Maximum Number of Balloons

#118

Rank

#3437MediumFrequency: 15.7%

Maximum Total Damage With Spell Casting

Array Hash Table Two Pointers Binary Search Dynamic Programming Sorting Counting

#119

Rank

#3493MediumFrequency: 14.6%

Maximum Number of Operations to Move Ones to the End

#120

Rank

#1786EasyFrequency: 14.6%

Count the Number of Consistent Strings

#121

Rank

#1500EasyFrequency: 14.6%

Count Largest Group

Hash Table Math Counting

#122

Rank

#3872EasyFrequency: 14.4%

Find Most Frequent Vowel and Consonant

#123

Rank

#1987EasyFrequency: 12%

Substrings of Size Three with Distinct Characters

Hash Table String Sliding Window Counting

#124

Rank

#3885MediumFrequency: 11.4%

Count Special Triplets

#125

Rank

#2532EasyFrequency: 10.5%

Remove Letter To Equalize Frequency

#126

Rank

#920EasyFrequency: 10.5%

Uncommon Words from Two Sentences

#127

Rank

#1354MediumFrequency: 10.5%

Find Players With Zero or One Losses

#128

Rank

#3813HardFrequency: 10.5%

Smallest Palindromic Rearrangement II

Hash Table Math String Combinatorics Counting

#129

Rank

#2129MediumFrequency: 10.3%

Number of Pairs of Interchangeable Rectangles

Array Hash Table Math Counting Number Theory

#130

Rank

#2486EasyFrequency: 8.1%

Most Frequent Even Element

#131

Rank

#3630HardFrequency: 8.1%

Total Characters in String After Transformations II

Hash Table Math String Dynamic Programming Counting

#132

Rank

#2356MediumFrequency: 8.1%

Largest Combination With Bitwise AND Greater Than Zero

#133

Rank

#959MediumFrequency: 8.1%

3Sum With Multiplicity

Array Hash Table Two Pointers Sorting Counting

#134

Rank

#3019EasyFrequency: 8%

Furthest Point From Origin

#135

Rank

#3403MediumFrequency: 7.3%

Minimum Substring Partition of Equal Character Frequency

Hash Table String Dynamic Programming Counting

#136

Rank

#2053EasyFrequency: 7.2%

Check if All Characters Have Equal Number of Occurrences

#137

Rank

#1823EasyFrequency: 5.5%

Determine if String Halves Are Alike

#138

Rank

#1913HardFrequency: 5.5%

Make the XOR of All Segments Equal to Zero

Array Hash Table Dynamic Programming Bit Manipulation Counting

#139

Rank

#3519EasyFrequency: 5.5%

Find the Number of Winning Players

#140

Rank

#2269EasyFrequency: 5.5%

Count Elements With Strictly Smaller and Greater Elements

#141

Rank

#3877MediumFrequency: 5.5%

Two-Letter Card Game

Array Hash Table String Counting Enumeration

#142

Rank

#3247MediumFrequency: 5%

Number of Same-End Substrings

Array Hash Table String Counting Prefix Sum

#143

Rank

#3418MediumFrequency: 5%

Count Pairs That Form a Complete Day II

#144

Rank

#3360MediumFrequency: 5%

Minimum Deletions to Make String K-Special

#145

Rank

#3324EasyFrequency: 5%

Split the Array

#146

Rank

#1472EasyFrequency: 5%

Increasing Decreasing String

#147

Rank

#3979MediumFrequency: 5%

Partition Array Into K-Distinct Groups

#148

Rank

#3957HardFrequency: 5%

Sum of Perfect Square Ancestors

Array Hash Table Math Tree Depth-First Search Counting Number Theory

#149

Rank

#2592HardFrequency: 5%

Minimum Total Cost to Make Arrays Unequal

#150

Rank

#2605HardFrequency: 5%

Count Anagrams

Hash Table Math String Combinatorics Counting Fermat's Little Theorem

#151

Rank

#4002HardFrequency: 5%

Count Subarrays With K Distinct Integers

#152

Rank

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Counting Interview Questions

Master 152 counting problems frequently asked in technical interviews. These questions test your understanding of countingconcepts and are essential for coding interview success.

152

Total Problems

Easy

Medium

Hard

Find Words That Can Be Formed by Characters

Rank

#347MediumFrequency: 81.3%

Top K Frequent Elements

Array Hash Table Divide and Conquer Sorting Heap (Priority Queue)Bucket Sort Counting Quickselect

Rank

#778MediumFrequency: 78.3%

Reorganize String

Hash Table String Greedy Sorting Heap (Priority Queue)Counting

Rank

#3994EasyFrequency: 76.6%

Find The Least Frequent Digit

Rank

#2301HardFrequency: 73.2%

Count Array Pairs Divisible by K

Array Hash Table Math Counting Number Theory Euclidean Algorithm Greatest Common Divisor

Rank

#2654EasyFrequency: 73.2%

Count the Number of Vowel Strings in Range

Array String Counting

Rank

#169EasyFrequency: 70.4%

Majority Element

Array Hash Table Divide and Conquer Sorting Counting Boyer–Moore Majority Vote Algorithm

Rank

#3778EasyFrequency: 69.8%

Transform Array by Parity

Rank

#3317MediumFrequency: 66.4%

Maximum Palindromes After Operations

Array Hash Table String Greedy Sorting Counting

Rank

#936MediumFrequency: 65.2%

RLE Iterator

Array Design Counting Iterator

#10

Rank

#1915EasyFrequency: 64.6%

Check if One String Swap Can Make Strings Equal

#11

Rank

#1469MediumFrequency: 63.5%

Minimum Number of Steps to Make Two Strings Anagram

#12

Rank

#621MediumFrequency: 63.1%

Task Scheduler

Array Hash Table Greedy Sorting Heap (Priority Queue)Counting

#13

Rank

#1055MediumFrequency: 62.2%

Pairs of Songs With Total Durations Divisible by 60

#14

Rank

#2237MediumFrequency: 61.1%

Longest Palindrome by Concatenating Two Letter Words

Array Hash Table String Greedy Counting

#15

Rank

#3736EasyFrequency: 60%

Find Valid Pair of Adjacent Digits in String

#16

Rank

#1341EasyFrequency: 59.6%

Split a String in Balanced Strings

#17

Rank

#3638HardFrequency: 59.3%

Minimum Operations to Make Character Frequencies Equal

Hash Table String Dynamic Programming Counting Enumeration

#18

Rank

#692MediumFrequency: 59.1%

Top K Frequent Words

Array Hash Table String Trie Sorting Heap (Priority Queue)Bucket Sort Counting

#19

Rank

#3594MediumFrequency: 58.8%

Identify the Largest Outlier in an Array

Array Hash Table Counting Enumeration

#20

Rank

#2594EasyFrequency: 55.8%

Count Pairs Of Similar Strings

#21

Rank

#387EasyFrequency: 55.2%

First Unique Character in a String

Hash Table String Queue Counting

#22

Rank

#2177EasyFrequency: 55.1%

Check Whether Two Strings are Almost Equivalent

#23

Rank

#383EasyFrequency: 55%

Ransom Note

#24

Rank

#982MediumFrequency: 50.3%

Minimum Increment to Make Array Unique

Array Greedy Sorting Counting

#25

Rank

#4253MediumFrequency: 49.9%

Minimum Cost to Equalize Arrays Using Swaps

#26

Rank

#2133MediumFrequency: 48.7%

Number of Pairs of Strings With Concatenation Equal to Target

#27

Rank

#1502MediumFrequency: 47.5%

Construct K Palindrome Strings

#28

Rank

#1643MediumFrequency: 47.5%

Number of Nodes in the Sub-Tree With the Same Label

Hash Table Tree Depth-First Search Breadth-First Search Counting DP on Trees

#29

Rank

#2331EasyFrequency: 47.5%

Intersection of Multiple Arrays

#30

Rank

#3335MediumFrequency: 47.5%

Minimum Operations to Write the Letter Y on a Grid

Array Hash Table Matrix Counting

#31

Rank

#1034HardFrequency: 46%

Subarrays with K Different Integers

#32

Rank

#451MediumFrequency: 43.2%

Sort Characters By Frequency

Hash Table String Sorting Heap (Priority Queue)Bucket Sort Counting

#33

Rank

#2270MediumFrequency: 43%

Find All Lonely Numbers in the Array

#34

Rank

#229MediumFrequency: 42.5%

Majority Element II

Array Hash Table Sorting Counting Boyer–Moore Majority Vote Algorithm

#35

Rank

#1708EasyFrequency: 41.4%

Design Parking System

Design Simulation Counting

#36

Rank

#3421EasyFrequency: 40.2%

Count Pairs That Form a Complete Day I

#37

Rank

#1510EasyFrequency: 35.7%

Find Lucky Integer in an Array

#38

Rank

#1983EasyFrequency: 35.7%

Maximum Population Year

Array Counting Prefix Sum

#39

Rank

#2308EasyFrequency: 34.3%

Divide Array Into Equal Pairs

#40

Rank

#1925MediumFrequency: 33.5%

Count Nice Pairs in an Array

#41

Rank

#3267MediumFrequency: 33.1%

Find Longest Special Substring That Occurs Thrice I

Hash Table String Binary Search Sliding Window Counting

#42

Rank

#1947HardFrequency: 31.3%

Number of Different Subsequences GCDs

Array Math Counting Number Theory Euclidean Algorithm Greatest Common Divisor

#43

Rank

#2139MediumFrequency: 31.1%

Detect Squares

Array Hash Table Design Counting Data Stream

#44

Rank

#1890MediumFrequency: 30.2%

Sum of Beauty of All Substrings

#45

Rank

#2433EasyFrequency: 29.5%

Best Poker Hand

#46

Rank

#2475MediumFrequency: 29.3%

Largest Palindromic Number

#47

Rank

#1227EasyFrequency: 29.1%

Number of Equivalent Domino Pairs

#48

Rank

#2289MediumFrequency: 29.1%

Minimum Operations to Make the Array Alternating

#49

Rank

#4061HardFrequency: 29.1%

Minimum Swaps to Avoid Forbidden Values

#50

Rank

#1635EasyFrequency: 28.9%

Number of Good Pairs

#51

Rank

#2378MediumFrequency: 28.1%

Sender With Largest Word Count

#52

Rank

#2135HardFrequency: 27.7%

Maximum Number of Ways to Partition an Array

Array Hash Table Counting Enumeration Prefix Sum

#53

Rank

#1604MediumFrequency: 27.7%

Least Number of Unique Integers after K Removals

#54

Rank

#1143MediumFrequency: 27.3%

Find Smallest Common Element in All Rows

Array Hash Table Binary Search Matrix Counting

#55

Rank

#594EasyFrequency: 27.2%

Longest Harmonious Subsequence

Array Hash Table Sliding Window Sorting Counting

#56

Rank

#1149EasyFrequency: 26.7%

Intersection of Three Sorted Arrays

Array Hash Table Binary Search Counting

#57

Rank

#1848EasyFrequency: 26.7%

Sum of Unique Elements

#58

Rank

#3707MediumFrequency: 26.7%

Find the Most Common Response

#59

Rank

#837EasyFrequency: 26.5%

Most Common Word

#60

Rank

#2116EasyFrequency: 26.5%

Count Number of Pairs With Absolute Difference K

#61

Rank

#2362MediumFrequency: 26.5%

Minimum Rounds to Complete All Tasks

#62

Rank

#3276MediumFrequency: 26.5%

Minimum Number of Pushes to Type Word II

#63

Rank

#1364MediumFrequency: 26.3%

Tuple with Same Product

#64

Rank

#2427EasyFrequency: 26.3%

First Letter to Appear Twice

Hash Table String Bit Manipulation Counting

#65

Rank

#1483MediumFrequency: 25.4%

Rank Teams by Votes

Array Hash Table String Sorting Counting

#66

Rank

#299MediumFrequency: 25.4%

Bulls and Cows

#67

Rank

#2448MediumFrequency: 25.4%

Count Number of Bad Pairs

#68

Rank

#1160MediumFrequency: 25.3%

Letter Tile Possibilities

Hash Table String Backtracking Counting

#69

Rank

#1381HardFrequency: 25.1%

Maximum Score Words Formed by Letters

Array Hash Table String Dynamic Programming Backtracking Bit Manipulation Counting Bitmask

#70

Rank

#1620MediumFrequency: 25.1%

Check If Array Pairs Are Divisible by k

#71

Rank

#3871EasyFrequency: 25.1%

Minimum Deletions for At Most K Distinct Characters

#72

Rank

#358HardFrequency: 24.6%

Rearrange String k Distance Apart

Hash Table String Greedy Sorting Heap (Priority Queue)Counting

#73

Rank

#950EasyFrequency: 24.4%

X of a Kind in a Deck of Cards

Array Hash Table Math Counting Number Theory Euclidean Algorithm Greatest Common Divisor

#74

Rank

#1396MediumFrequency: 24.4%

Count Servers that Communicate

Array Depth-First Search Breadth-First Search Union-Find Matrix Counting

#75

Rank

#1140MediumFrequency: 23.6%

Distant Barcodes

Array Hash Table Greedy Sorting Heap (Priority Queue)Counting

#76

Rank

#3094MediumFrequency: 23.6%

Minimum Number of Operations to Make Array Empty

#77

Rank

#3955HardFrequency: 23.4%

Threshold Majority Queries

Array Hash Table Binary Search Divide and Conquer Counting Prefix Sum

#78

Rank

#1777MediumFrequency: 22%

Determine if Two Strings Are Close

Hash Table String Sorting Counting

#79

Rank

#2405MediumFrequency: 21.9%

Minimum Number of Keypresses

#80

Rank

#3242EasyFrequency: 21.9%

Count Elements With Maximum Frequency

#81

Rank

#3354MediumFrequency: 21.9%

Replace Question Marks in String to Minimize Its Value

Hash Table String Greedy Sorting Heap (Priority Queue)Counting

#82

Rank

#2140HardFrequency: 21.5%

Longest Subsequence Repeated k Times

Hash Table Two Pointers String Backtracking Counting Enumeration

#83

Rank

#1986HardFrequency: 20.9%

Largest Color Value in a Directed Graph

Hash Table String Dynamic Programming Graph Theory Topological Sort Memoization Counting Directed Acyclic Graph

#84

Rank

#900MediumFrequency: 20.9%

Reordered Power of 2

Hash Table Math Sorting Counting Enumeration

#85

Rank

#3754MediumFrequency: 20.3%

Maximum Manhattan Distance After K Changes

Hash Table Math String Counting

#86

Rank

#1891HardFrequency: 20%

Count Pairs Of Nodes

Array Hash Table Two Pointers Binary Search Graph Theory Sorting Counting

#87

Rank

#2163EasyFrequency: 20%

Kth Distinct String in an Array

#88

Rank

#2372EasyFrequency: 20%

Rearrange Characters to Make Target String

#89

Rank

#2995MediumFrequency: 20%

Number of Unique Categories

Union-Find Interactive Counting

#90

Rank

#2312EasyFrequency: 19.5%

Most Frequent Number Following Key In an Array

#91

Rank

#2377EasyFrequency: 19.5%

Check if Number Has Equal Digit Count and Digit Value

#92

Rank

#2494HardFrequency: 19.5%

Sum of Prefix Scores of Strings

Array String Trie Counting

#93

Rank

#2525MediumFrequency: 19.5%

Count Number of Distinct Integers After Reverse Operations

#94

Rank

#829MediumFrequency: 19.5%

Subdomain Visit Count

#95

Rank

#4183MediumFrequency: 19.5%

Count Caesar Cipher Pairs

Array Hash Table Math String Counting

#96

Rank

#2300MediumFrequency: 19.5%

Construct String With Repeat Limit

Hash Table String Greedy Heap (Priority Queue)Counting

#97

Rank

#3753EasyFrequency: 19.5%

Maximum Difference Between Even and Odd Frequency I

#98

Rank

#1458EasyFrequency: 19.5%

Sort Integers by The Number of 1 Bits

Array Bit Manipulation Sorting Counting

#99

Rank

#4074MediumFrequency: 19.5%

Count Subarrays With Majority Element I

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

#100

Rank

#1758HardFrequency: 18%

Distribute Repeating Integers

Array Hash Table Dynamic Programming Backtracking Bit Manipulation Counting Bitmask

#101

Rank

#2615MediumFrequency: 18%

Make Number of Distinct Characters Equal

#102

Rank

#3266MediumFrequency: 18%

Find Longest Special Substring That Occurs Thrice II

Hash Table String Binary Search Sliding Window Counting

#103

Rank

#3384MediumFrequency: 18%

Minimum Number of Operations to Make Word K-Periodic

#104

Rank

#3416MediumFrequency: 18%

Sum of Digit Differences of All Pairs

#105

Rank

#3629MediumFrequency: 18%

Total Characters in String After Transformations I

Hash Table Math String Dynamic Programming Counting

#106

Rank

#4020MediumFrequency: 18%

Lexicographically Smallest Permutation Greater Than Target

Hash Table String Greedy Counting Enumeration

#107

Rank

#4055MediumFrequency: 18%

Longest Balanced Substring I

Hash Table String Counting Enumeration

#108

Rank

#1118HardFrequency: 16.4%

Divide Array Into Increasing Sequences

Array Counting

#109

Rank

#1169MediumFrequency: 16.4%

Largest Values From Labels

#110

Rank

#1750MediumFrequency: 16.4%

Check If Two Expression Trees are Equivalent

Hash Table Tree Depth-First Search Binary Tree Counting

#111

Rank

#1859MediumFrequency: 16.4%

Change Minimum Characters to Satisfy One of Three Conditions

Hash Table String Counting Prefix Sum

#112

Rank

#2071MediumFrequency: 16.4%

Longest Common Subsequence Between Sorted Arrays

#113

Rank

#3314MediumFrequency: 16.4%

Most Frequent Prime

Array Hash Table Math Matrix Counting Enumeration Number Theory Primality Test Sieve Theory Prime Number Sieve

#114

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

#115

Rank

#2174MediumFrequency: 16.4%

Next Greater Numerically Balanced Number

Hash Table Math Backtracking Counting Enumeration

#116

Rank

#2614EasyFrequency: 16.1%

Maximum Count of Positive Integer and Negative Integer

Array Binary Search Counting

#117

Rank

#1297EasyFrequency: 16.1%

Maximum Number of Balloons

#118

Rank

#3437MediumFrequency: 15.7%

Maximum Total Damage With Spell Casting

Array Hash Table Two Pointers Binary Search Dynamic Programming Sorting Counting

#119

Rank

#3493MediumFrequency: 14.6%

Maximum Number of Operations to Move Ones to the End

#120

Rank

#1786EasyFrequency: 14.6%

Count the Number of Consistent Strings

#121

Rank

#1500EasyFrequency: 14.6%

Count Largest Group

Hash Table Math Counting

#122

Rank

#3872EasyFrequency: 14.4%

Find Most Frequent Vowel and Consonant

#123

Rank

#1987EasyFrequency: 12%

Substrings of Size Three with Distinct Characters

Hash Table String Sliding Window Counting

#124

Rank

#3885MediumFrequency: 11.4%

Count Special Triplets

#125

Rank

#2532EasyFrequency: 10.5%

Remove Letter To Equalize Frequency

#126

Rank

#920EasyFrequency: 10.5%

Uncommon Words from Two Sentences

#127

Rank

#1354MediumFrequency: 10.5%

Find Players With Zero or One Losses

#128

Rank

#3813HardFrequency: 10.5%

Smallest Palindromic Rearrangement II

Hash Table Math String Combinatorics Counting

#129

Rank

#2129MediumFrequency: 10.3%

Number of Pairs of Interchangeable Rectangles

Array Hash Table Math Counting Number Theory

#130

Rank

#2486EasyFrequency: 8.1%

Most Frequent Even Element

#131

Rank

#3630HardFrequency: 8.1%

Total Characters in String After Transformations II

Hash Table Math String Dynamic Programming Counting

#132

Rank

#2356MediumFrequency: 8.1%

Largest Combination With Bitwise AND Greater Than Zero

#133

Rank

#959MediumFrequency: 8.1%

3Sum With Multiplicity

Array Hash Table Two Pointers Sorting Counting

#134

Rank

#3019EasyFrequency: 8%

Furthest Point From Origin

#135

Rank

#3403MediumFrequency: 7.3%

Minimum Substring Partition of Equal Character Frequency

Hash Table String Dynamic Programming Counting

#136

Rank

#2053EasyFrequency: 7.2%

Check if All Characters Have Equal Number of Occurrences

#137

Rank

#1823EasyFrequency: 5.5%

Determine if String Halves Are Alike

#138

Rank

#1913HardFrequency: 5.5%

Make the XOR of All Segments Equal to Zero

Array Hash Table Dynamic Programming Bit Manipulation Counting

#139

Rank

#3519EasyFrequency: 5.5%

Find the Number of Winning Players

#140

Rank

#2269EasyFrequency: 5.5%

Count Elements With Strictly Smaller and Greater Elements

#141

Rank

#3877MediumFrequency: 5.5%

Two-Letter Card Game

Array Hash Table String Counting Enumeration

#142

Rank

#3247MediumFrequency: 5%

Number of Same-End Substrings

Array Hash Table String Counting Prefix Sum

#143

Rank

#3418MediumFrequency: 5%

Count Pairs That Form a Complete Day II

#144

Rank

#3360MediumFrequency: 5%

Minimum Deletions to Make String K-Special

#145

Rank

#3324EasyFrequency: 5%

Split the Array

#146

Rank

#1472EasyFrequency: 5%

Increasing Decreasing String

#147

Rank

#3979MediumFrequency: 5%

Partition Array Into K-Distinct Groups

#148

Rank

#3957HardFrequency: 5%

Sum of Perfect Square Ancestors

Array Hash Table Math Tree Depth-First Search Counting Number Theory

#149

Rank

#2592HardFrequency: 5%

Minimum Total Cost to Make Arrays Unequal

#150

Rank

#2605HardFrequency: 5%

Count Anagrams

Hash Table Math String Combinatorics Counting Fermat's Little Theorem

#151

Rank

#4002HardFrequency: 5%

Count Subarrays With K Distinct Integers