Two Pointers Interview Questions

Array Hash Table Two Pointers Binary Search Sorting

Rank

#295HardFrequency: 100%

Find Median from Data Stream

Asked at PayPal

Two Pointers Design Sorting Heap (Priority Queue)Data Stream

Rank

#658MediumFrequency: 96%

Find K Closest Elements

Asked at DoorDash

Array Two Pointers Binary Search Sliding Window Sorting Heap (Priority Queue)

Rank

#680EasyFrequency: 95%

Valid Palindrome II

Two Pointers String Greedy

Rank

#88EasyFrequency: 92%

Merge Sorted Array

Rank

#1790MediumFrequency: 91%

Lowest Common Ancestor of a Binary Tree III

Hash Table Two Pointers Tree Binary Tree

Rank

#647MediumFrequency: 88%

Palindromic Substrings

Rank

#408EasyFrequency: 87%

Valid Word Abbreviation

Rank

#125EasyFrequency: 87%

Valid Palindrome

Asked at Oracle

Rank

#1894EasyFrequency: 80%

Merge Strings Alternately

#10

Rank

#1713MediumFrequency: 76%

Dot Product of Two Sparse Vectors

Array Hash Table Two Pointers Design

#11

Rank

#42HardFrequency: 74%

Trapping Rain Water

Array Two Pointers Dynamic Programming Stack Monotonic Stack

#12

Rank

#27EasyFrequency: 73%

Remove Element

#13

Rank

#277MediumFrequency: 72%

Find the Celebrity

Two Pointers Graph Interactive

#14

Rank

#1028MediumFrequency: 69%

Interval List Intersections

#15

Rank

#283EasyFrequency: 66%

Move Zeroes

#16

Rank

#1019EasyFrequency: 63%

Squares of a Sorted Array

Asked at Uber

#17

Rank

#244MediumFrequency: 63%

Shortest Word Distance II

Array Hash Table Two Pointers String Design

#18

Rank

#31MediumFrequency: 62%

Next Permutation

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

#19

Rank

#253MediumFrequency: 62%

Meeting Rooms II

Asked at TikTok

#20

Rank

#2414MediumFrequency: 60%

Move Pieces to Obtain a String

#21

Rank

#15MediumFrequency: 60%

3Sum

#22

Rank

#3018MediumFrequency: 60%

Make String a Subsequence Using Cyclic Increments

#23

Rank

#5MediumFrequency: 55%

Longest Palindromic Substring

#24

Rank

#18MediumFrequency: 55%

4Sum

#25

Rank

#167MediumFrequency: 55%

Two Sum II - Input Array Is Sorted

Array Two Pointers Binary Search

#26

Rank

#567MediumFrequency: 55%

Permutation in String

Hash Table Two Pointers String Sliding Window

#27

Rank

#1468EasyFrequency: 55%

Check If N and Its Double Exist

Array Hash Table Two Pointers Binary Search Sorting

#28

Rank

#1566EasyFrequency: 55%

Check If a Word Occurs As a Prefix of Any Word in a Sentence

#29

Rank

#26EasyFrequency: 53%

Remove Duplicates from Sorted Array

#30

Rank

#141EasyFrequency: 53%

Linked List Cycle

Hash Table Linked List Two Pointers

#31

Rank

#28EasyFrequency: 48%

Find the Index of the First Occurrence in a String

#32

Rank

#234EasyFrequency: 48%

Palindrome Linked List

Linked List Two Pointers Stack Recursion

#33

Rank

#2232MediumFrequency: 48%

Adding Spaces to a String

Array Two Pointers String Simulation

#34

Rank

#151MediumFrequency: 45%

Reverse Words in a String

#35

Rank

#19MediumFrequency: 43%

Remove Nth Node From End of List

Linked List Two Pointers

#36

Rank

#11MediumFrequency: 42%

Container With Most Water

Array Two Pointers Greedy

#37

Rank

#75MediumFrequency: 42%

Sort Colors

#38

Rank

#852MediumFrequency: 37%

Friends Of Appropriate Ages

Array Two Pointers Binary Search Sorting

#39

Rank

#80MediumFrequency: 36%

Remove Duplicates from Sorted Array II

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#40

Rank

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Two Pointers Interview Questions

Master 40 two pointers problems frequently asked in technical interviews. These questions test your understanding of two pointersconcepts and are essential for coding interview success.

Total Problems

Easy

Medium

Hard

K-diff Pairs in an Array

Array Hash Table Two Pointers Binary Search Sorting

Rank

#295HardFrequency: 100%

Find Median from Data Stream

Asked at PayPal

Two Pointers Design Sorting Heap (Priority Queue)Data Stream

Rank

#658MediumFrequency: 96%

Find K Closest Elements

Asked at DoorDash

Array Two Pointers Binary Search Sliding Window Sorting Heap (Priority Queue)

Rank

#680EasyFrequency: 95%

Valid Palindrome II

Two Pointers String Greedy

Rank

#88EasyFrequency: 92%

Merge Sorted Array

Rank

#1790MediumFrequency: 91%

Lowest Common Ancestor of a Binary Tree III

Hash Table Two Pointers Tree Binary Tree

Rank

#647MediumFrequency: 88%

Palindromic Substrings

Rank

#408EasyFrequency: 87%

Valid Word Abbreviation

Rank

#125EasyFrequency: 87%

Valid Palindrome

Asked at Oracle

Rank

#1894EasyFrequency: 80%

Merge Strings Alternately

#10

Rank

#1713MediumFrequency: 76%

Dot Product of Two Sparse Vectors

Array Hash Table Two Pointers Design

#11

Rank

#42HardFrequency: 74%

Trapping Rain Water

Array Two Pointers Dynamic Programming Stack Monotonic Stack

#12

Rank

#27EasyFrequency: 73%

Remove Element

#13

Rank

#277MediumFrequency: 72%

Find the Celebrity

Two Pointers Graph Interactive

#14

Rank

#1028MediumFrequency: 69%

Interval List Intersections

#15

Rank

#283EasyFrequency: 66%

Move Zeroes

#16

Rank

#1019EasyFrequency: 63%

Squares of a Sorted Array

Asked at Uber

#17

Rank

#244MediumFrequency: 63%

Shortest Word Distance II

Array Hash Table Two Pointers String Design

#18

Rank

#31MediumFrequency: 62%

Next Permutation

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

#19

Rank

#253MediumFrequency: 62%

Meeting Rooms II

Asked at TikTok

#20

Rank

#2414MediumFrequency: 60%

Move Pieces to Obtain a String

#21

Rank

#15MediumFrequency: 60%

3Sum

#22

Rank

#3018MediumFrequency: 60%

Make String a Subsequence Using Cyclic Increments

#23

Rank

#5MediumFrequency: 55%

Longest Palindromic Substring

#24

Rank

#18MediumFrequency: 55%

4Sum

#25

Rank

#167MediumFrequency: 55%

Two Sum II - Input Array Is Sorted

Array Two Pointers Binary Search

#26

Rank

#567MediumFrequency: 55%

Permutation in String

Hash Table Two Pointers String Sliding Window

#27

Rank

#1468EasyFrequency: 55%

Check If N and Its Double Exist

Array Hash Table Two Pointers Binary Search Sorting

#28

Rank

#1566EasyFrequency: 55%

Check If a Word Occurs As a Prefix of Any Word in a Sentence

#29

Rank

#26EasyFrequency: 53%

Remove Duplicates from Sorted Array

#30

Rank

#141EasyFrequency: 53%

Linked List Cycle

Hash Table Linked List Two Pointers

#31

Rank

#28EasyFrequency: 48%

Find the Index of the First Occurrence in a String

#32

Rank

#234EasyFrequency: 48%

Palindrome Linked List

Linked List Two Pointers Stack Recursion

#33

Rank

#2232MediumFrequency: 48%

Adding Spaces to a String

Array Two Pointers String Simulation

#34

Rank

#151MediumFrequency: 45%

Reverse Words in a String

#35

Rank

#19MediumFrequency: 43%

Remove Nth Node From End of List

Linked List Two Pointers

#36

Rank

#11MediumFrequency: 42%

Container With Most Water

Array Two Pointers Greedy

#37

Rank

#75MediumFrequency: 42%

Sort Colors

#38

Rank

#852MediumFrequency: 37%

Friends Of Appropriate Ages

Array Two Pointers Binary Search Sorting

#39

Rank

#80MediumFrequency: 36%

Remove Duplicates from Sorted Array II