Monotonic Stack Interview Questions

Array Two Pointers Dynamic Programming Stack Monotonic Stack

Rank

#1909MediumFrequency: 82.6%

Buildings With an Ocean View

Rank

#2419HardFrequency: 69.8%

Subarray With Elements Greater Than Varying Threshold

Array Stack Union-Find Monotonic Stack

Rank

#3181HardFrequency: 69.8%

Find Building Where Alice and Bob Can Meet

Array Binary Search Stack Binary Indexed Tree Segment Tree Heap (Priority Queue)Monotonic Stack

Rank

#84HardFrequency: 69.6%

Largest Rectangle in Histogram

Array Stack Monotonic Stack Range Minimum/Maximum Query

Rank

#1570EasyFrequency: 63.1%

Final Prices With a Special Discount in a Shop

Rank

#1219MediumFrequency: 62.5%

Longest Well-Performing Interval

Array Hash Table Stack Monotonic Stack Prefix Sum

Rank

#739MediumFrequency: 61.4%

Daily Temperatures

Rank

#321HardFrequency: 59.8%

Create Maximum Number

Array Two Pointers Stack Greedy Monotonic Stack

Rank

#943MediumFrequency: 59.8%

Sum of Subarray Minimums

#10

Rank

#1633HardFrequency: 56.5%

Minimum Number of Increments on Subarrays to Form a Target Array

Array Dynamic Programming Stack Greedy Monotonic Stack

#11

Rank

#3113MediumFrequency: 55.1%

Beautiful Towers II

#12

Rank

#3114MediumFrequency: 55.1%

Beautiful Towers I

#13

Rank

#496EasyFrequency: 54.7%

Next Greater Element I

Array Hash Table Stack Monotonic Stack

#14

Rank

#316MediumFrequency: 54.4%

Remove Duplicate Letters

#15

Rank

#503MediumFrequency: 54.1%

Next Greater Element II

#16

Rank

#1305HardFrequency: 52.9%

Number of Visible People in a Queue

Array Binary Search Stack Monotonic Stack Ordered Set

#17

Rank

#456MediumFrequency: 51.3%

132 Pattern

Asked at DoorDash

#18

Rank

#85HardFrequency: 51.1%

Maximal Rectangle

Array Dynamic Programming Stack Matrix Monotonic Stack

#19

Rank

#1985MediumFrequency: 49.9%

Maximum Subarray Min-Product

Array Stack Monotonic Stack Prefix Sum Cartesian Tree

#20

Rank

#2425MediumFrequency: 47.5%

Number of People That Can Be Seen in a Grid

Array Stack Matrix Monotonic Stack

#21

Rank

#937MediumFrequency: 45.8%

Online Stock Span

Stack Design Monotonic Stack Data Stream

#22

Rank

#402MediumFrequency: 45.1%

Remove K Digits

#23

Rank

#581MediumFrequency: 44%

Shortest Unsorted Continuous Subarray

Array Two Pointers Stack Greedy Sorting Monotonic Stack

#24

Rank

#255MediumFrequency: 41.2%

Verify Preorder Sequence in Binary Search Tree

Array Stack Tree Binary Search Tree Recursion Monotonic Stack Binary Tree

#25

Rank

#2368HardFrequency: 40.2%

Sum of Total Strength of Wizards

Array Stack Monotonic Stack Prefix Sum

#26

Rank

#2227MediumFrequency: 39.5%

Sum of Subarray Ranges

#27

Rank

#1002MediumFrequency: 39%

Maximum Width Ramp

Array Two Pointers Stack Monotonic Stack

#28

Rank

#1050MediumFrequency: 37.4%

Construct Binary Search Tree from Preorder Traversal

Array Stack Tree Binary Search Tree Monotonic Stack Binary Tree

#29

Rank

#1017HardFrequency: 35.8%

Odd Even Jump

Array Dynamic Programming Stack Sorting Monotonic Stack Ordered Set

#30

Rank

#1159MediumFrequency: 35.1%

Smallest Subsequence of Distinct Characters

#31

Rank

#1072MediumFrequency: 32.8%

Next Greater Node In Linked List

Array Linked List Stack Monotonic Stack

#32

Rank

#883MediumFrequency: 31.8%

Car Fleet

#33

Rank

#4000MediumFrequency: 31.3%

Count Bowl Subarrays

#34

Rank

#3454HardFrequency: 29.3%

Minimum Operations to Make Array Equal to Target

Array Dynamic Programming Stack Greedy Monotonic Stack

#35

Rank

#2490HardFrequency: 29.1%

Maximum Number of Books You Can Take

#36

Rank

#780MediumFrequency: 28.1%

Max Chunks To Make Sorted

#37

Rank

#2111MediumFrequency: 27.8%

Binary Searchable Numbers in an Unsorted Array

#38

Rank

#779HardFrequency: 27.7%

Max Chunks To Make Sorted II

#39

Rank

#2485MediumFrequency: 27.7%

Finding the Number of Visible Mountains

#40

Rank

#654MediumFrequency: 27.3%

Maximum Binary Tree

Array Divide and Conquer Stack Tree Monotonic Stack Binary Tree Cartesian Tree

#41

Rank

#4222HardFrequency: 27.3%

Count Good Subarrays

Array Stack Bit Manipulation Monotonic Stack

#42

Rank

#1679MediumFrequency: 26.5%

Shortest Subarray to be Removed to Make Array Sorted

Array Two Pointers Binary Search Stack Monotonic Stack

#43

Rank

#1628MediumFrequency: 26.3%

Count Submatrices With All Ones

Array Dynamic Programming Stack Matrix Monotonic Stack

#44

Rank

#1792MediumFrequency: 25.4%

Find the Most Competitive Subsequence

#45

Rank

#3211HardFrequency: 24.6%

Find Maximum Non-decreasing Array Length

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

#46

Rank

#3674HardFrequency: 24.4%

Count Non-Decreasing Subarrays After K Operations

Array Stack Segment Tree Queue Sliding Window Monotonic Stack Monotonic Queue

#47

Rank

#2573MediumFrequency: 23.6%

Remove Nodes From Linked List

Linked List Stack Recursion Monotonic Stack

#48

Rank

#2374MediumFrequency: 21.5%

Steps to Make Array Non-decreasing

Array Linked List Dynamic Programming Stack Monotonic Stack Simulation

#49

Rank

#1918HardFrequency: 20.9%

Maximum Score of a Good Subarray

Array Two Pointers Binary Search Stack Monotonic Stack Cartesian Tree

#50

Rank

#2123MediumFrequency: 20.9%

The Number of Weak Characters in the Game

#51

Rank

#1902HardFrequency: 20.9%

Car Fleet II

Array Math Stack Heap (Priority Queue)Monotonic Stack

#52

Rank

#2056MediumFrequency: 20%

Jump Game VIII

Array Dynamic Programming Stack Graph Theory Monotonic Stack Shortest Path

#53

Rank

#2072MediumFrequency: 20%

Maximum of Minimum Values in All Subarrays

Array Stack Monotonic Stack Cartesian Tree

#54

Rank

#3088MediumFrequency: 20%

Maximal Range That Each Element Is Maximum in It

#55

Rank

#3382HardFrequency: 20%

Find the Number of Subarrays Where Boundary Elements Are Maximum

#56

Rank

#3158MediumFrequency: 18%

Maximum Length of Semi-Decreasing Subarrays

#57

Rank

#3954MediumFrequency: 15.7%

Maximum Balanced Shipments

Array Dynamic Programming Stack Greedy Monotonic Stack

#58

Rank

#1228MediumFrequency: 10.5%

Minimum Cost Tree From Leaf Values

Array Dynamic Programming Stack Greedy Monotonic Stack Cartesian Tree

#59

Rank

#3001HardFrequency: 10.5%

Apply Operations to Maximize Score

Array Math Stack Greedy Sorting Monotonic Stack Number Theory

#60

Rank

#3834MediumFrequency: 10.5%

Minimum Operations to Convert All Elements to Zero

Array Hash Table Stack Greedy Monotonic Stack

#61

Rank

#3738MediumFrequency: 8.1%

Make Array Non-decreasing

#62

Rank

#4086HardFrequency: 5%

Lexicographically Smallest String After Deleting Duplicate Characters

Hash Table String Stack Greedy Monotonic Stack

#63

Rank

#2549HardFrequency: 5%

Next Greater Element IV

Array Binary Search Stack Sorting Heap (Priority Queue)Monotonic Stack

#64

Rank

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Monotonic Stack Interview Questions

Master 64 monotonic stack problems frequently asked in technical interviews. These questions test your understanding of monotonic stackconcepts and are essential for coding interview success.

Total Problems

Easy

Medium

Hard

Trapping Rain Water

Array Two Pointers Dynamic Programming Stack Monotonic Stack

Rank

#1909MediumFrequency: 82.6%

Buildings With an Ocean View

Rank

#2419HardFrequency: 69.8%

Subarray With Elements Greater Than Varying Threshold

Array Stack Union-Find Monotonic Stack

Rank

#3181HardFrequency: 69.8%

Find Building Where Alice and Bob Can Meet

Array Binary Search Stack Binary Indexed Tree Segment Tree Heap (Priority Queue)Monotonic Stack

Rank

#84HardFrequency: 69.6%

Largest Rectangle in Histogram

Array Stack Monotonic Stack Range Minimum/Maximum Query

Rank

#1570EasyFrequency: 63.1%

Final Prices With a Special Discount in a Shop

Rank

#1219MediumFrequency: 62.5%

Longest Well-Performing Interval

Array Hash Table Stack Monotonic Stack Prefix Sum

Rank

#739MediumFrequency: 61.4%

Daily Temperatures

Rank

#321HardFrequency: 59.8%

Create Maximum Number

Array Two Pointers Stack Greedy Monotonic Stack

Rank

#943MediumFrequency: 59.8%

Sum of Subarray Minimums

#10

Rank

#1633HardFrequency: 56.5%

Minimum Number of Increments on Subarrays to Form a Target Array

Array Dynamic Programming Stack Greedy Monotonic Stack

#11

Rank

#3113MediumFrequency: 55.1%

Beautiful Towers II

#12

Rank

#3114MediumFrequency: 55.1%

Beautiful Towers I

#13

Rank

#496EasyFrequency: 54.7%

Next Greater Element I

Array Hash Table Stack Monotonic Stack

#14

Rank

#316MediumFrequency: 54.4%

Remove Duplicate Letters

#15

Rank

#503MediumFrequency: 54.1%

Next Greater Element II

#16

Rank

#1305HardFrequency: 52.9%

Number of Visible People in a Queue

Array Binary Search Stack Monotonic Stack Ordered Set

#17

Rank

#456MediumFrequency: 51.3%

132 Pattern

Asked at DoorDash

#18

Rank

#85HardFrequency: 51.1%

Maximal Rectangle

Array Dynamic Programming Stack Matrix Monotonic Stack

#19

Rank

#1985MediumFrequency: 49.9%

Maximum Subarray Min-Product

Array Stack Monotonic Stack Prefix Sum Cartesian Tree

#20

Rank

#2425MediumFrequency: 47.5%

Number of People That Can Be Seen in a Grid

Array Stack Matrix Monotonic Stack

#21

Rank

#937MediumFrequency: 45.8%

Online Stock Span

Stack Design Monotonic Stack Data Stream

#22

Rank

#402MediumFrequency: 45.1%

Remove K Digits

#23

Rank

#581MediumFrequency: 44%

Shortest Unsorted Continuous Subarray

Array Two Pointers Stack Greedy Sorting Monotonic Stack

#24

Rank

#255MediumFrequency: 41.2%

Verify Preorder Sequence in Binary Search Tree

Array Stack Tree Binary Search Tree Recursion Monotonic Stack Binary Tree

#25

Rank

#2368HardFrequency: 40.2%

Sum of Total Strength of Wizards

Array Stack Monotonic Stack Prefix Sum

#26

Rank

#2227MediumFrequency: 39.5%

Sum of Subarray Ranges

#27

Rank

#1002MediumFrequency: 39%

Maximum Width Ramp

Array Two Pointers Stack Monotonic Stack

#28

Rank

#1050MediumFrequency: 37.4%

Construct Binary Search Tree from Preorder Traversal

Array Stack Tree Binary Search Tree Monotonic Stack Binary Tree

#29

Rank

#1017HardFrequency: 35.8%

Odd Even Jump

Array Dynamic Programming Stack Sorting Monotonic Stack Ordered Set

#30

Rank

#1159MediumFrequency: 35.1%

Smallest Subsequence of Distinct Characters

#31

Rank

#1072MediumFrequency: 32.8%

Next Greater Node In Linked List

Array Linked List Stack Monotonic Stack

#32

Rank

#883MediumFrequency: 31.8%

Car Fleet

#33

Rank

#4000MediumFrequency: 31.3%

Count Bowl Subarrays

#34

Rank

#3454HardFrequency: 29.3%

Minimum Operations to Make Array Equal to Target

Array Dynamic Programming Stack Greedy Monotonic Stack

#35

Rank

#2490HardFrequency: 29.1%

Maximum Number of Books You Can Take

#36

Rank

#780MediumFrequency: 28.1%

Max Chunks To Make Sorted

#37

Rank

#2111MediumFrequency: 27.8%

Binary Searchable Numbers in an Unsorted Array

#38

Rank

#779HardFrequency: 27.7%

Max Chunks To Make Sorted II

#39

Rank

#2485MediumFrequency: 27.7%

Finding the Number of Visible Mountains

#40

Rank

#654MediumFrequency: 27.3%

Maximum Binary Tree

Array Divide and Conquer Stack Tree Monotonic Stack Binary Tree Cartesian Tree

#41

Rank

#4222HardFrequency: 27.3%

Count Good Subarrays

Array Stack Bit Manipulation Monotonic Stack

#42

Rank

#1679MediumFrequency: 26.5%

Shortest Subarray to be Removed to Make Array Sorted

Array Two Pointers Binary Search Stack Monotonic Stack

#43

Rank

#1628MediumFrequency: 26.3%

Count Submatrices With All Ones

Array Dynamic Programming Stack Matrix Monotonic Stack

#44

Rank

#1792MediumFrequency: 25.4%

Find the Most Competitive Subsequence

#45

Rank

#3211HardFrequency: 24.6%

Find Maximum Non-decreasing Array Length

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

#46

Rank

#3674HardFrequency: 24.4%

Count Non-Decreasing Subarrays After K Operations

Array Stack Segment Tree Queue Sliding Window Monotonic Stack Monotonic Queue

#47

Rank

#2573MediumFrequency: 23.6%

Remove Nodes From Linked List

Linked List Stack Recursion Monotonic Stack

#48

Rank

#2374MediumFrequency: 21.5%

Steps to Make Array Non-decreasing

Array Linked List Dynamic Programming Stack Monotonic Stack Simulation

#49

Rank

#1918HardFrequency: 20.9%

Maximum Score of a Good Subarray

Array Two Pointers Binary Search Stack Monotonic Stack Cartesian Tree

#50

Rank

#2123MediumFrequency: 20.9%

The Number of Weak Characters in the Game

#51

Rank

#1902HardFrequency: 20.9%

Car Fleet II

Array Math Stack Heap (Priority Queue)Monotonic Stack

#52

Rank

#2056MediumFrequency: 20%

Jump Game VIII

Array Dynamic Programming Stack Graph Theory Monotonic Stack Shortest Path

#53

Rank

#2072MediumFrequency: 20%

Maximum of Minimum Values in All Subarrays

Array Stack Monotonic Stack Cartesian Tree

#54

Rank

#3088MediumFrequency: 20%

Maximal Range That Each Element Is Maximum in It

#55

Rank

#3382HardFrequency: 20%

Find the Number of Subarrays Where Boundary Elements Are Maximum

#56

Rank

#3158MediumFrequency: 18%

Maximum Length of Semi-Decreasing Subarrays

#57

Rank

#3954MediumFrequency: 15.7%

Maximum Balanced Shipments

Array Dynamic Programming Stack Greedy Monotonic Stack

#58

Rank

#1228MediumFrequency: 10.5%

Minimum Cost Tree From Leaf Values

Array Dynamic Programming Stack Greedy Monotonic Stack Cartesian Tree

#59

Rank

#3001HardFrequency: 10.5%

Apply Operations to Maximize Score

Array Math Stack Greedy Sorting Monotonic Stack Number Theory

#60

Rank

#3834MediumFrequency: 10.5%

Minimum Operations to Convert All Elements to Zero

Array Hash Table Stack Greedy Monotonic Stack

#61

Rank

#3738MediumFrequency: 8.1%

Make Array Non-decreasing

#62

Rank

#4086HardFrequency: 5%

Lexicographically Smallest String After Deleting Duplicate Characters

Hash Table String Stack Greedy Monotonic Stack

#63

Rank

#2549HardFrequency: 5%

Next Greater Element IV