Valid Palindrome (LeetCode 125)
The problem You get a string that can contain letters, digits, spaces and…
Tag
#two-pointers
24 posts
Trapping Rain Water (LeetCode 42)
The problem You get an array of non-negative integers; each is the height of a…
Two Sum II – Input Array Is Sorted (LeetCode 167)
The problem You get an array sorted in non-decreasing order and a . Exactly one…
Squares of a Sorted Array (LeetCode 977)
The problem You get an integer array sorted in non-decreasing order. It may…
Sort Colors (LeetCode 75)
The problem You get an array containing only , and (red, white and blue…
Reverse Words in a String (LeetCode 151)
The problem You get a string of words separated by spaces. Return the words in…
Reverse Linked List (LeetCode 206)
The problem You get the of a singly linked list. Reverse the list so the last…
Remove Nth Node From End of List (LeetCode 19)
The problem You get the of a singly linked list and an integer . Remove the n…
Remove Duplicates from Sorted List II (LeetCode 82)
The problem You get the of a linked list sorted in ascending order. Remove…
Remove Duplicates from Sorted Array (LeetCode 26)
The problem You get an integer array sorted in non-decreasing order. Rearrange…
Palindromic Substrings (LeetCode 647)
The problem Given a string , count how many of its substrings are palindromes…
Odd Even Linked List (LeetCode 328)
The problem You get the of a linked list. Reorder it so all nodes at odd…
Move Zeroes (LeetCode 283)
The problem You get an integer array . Move all the s to the end in place, while…
Intersection of Two Linked Lists (LeetCode 160)
The problem You get the heads of two singly linked lists, and . At some node…
Interval List Intersections (LeetCode 986)
The problem You get two lists of closed intervals, and . Each list is sorted…
Container With Most Water (LeetCode 11)
The problem You get an array where is the height of a vertical wall at…
Backspace String Compare (LeetCode 844)
The problem You get two strings and that were typed into a text editor. The…
Assign Cookies (LeetCode 455)
The problem Each child has a greed factor : the smallest cookie size that makes…
3Sum (LeetCode 15)
The problem You get an integer array . Return every unique triplet of values…
4Sum (LeetCode 18)
The problem You get an integer array and a . Return every unique quadruplet…
3Sum Closest (LeetCode 16)
The problem You get an integer array (at least three numbers) and a . Choose…
Coding Interview Patterns — Crack the Coding Round
There are thousands of coding-interview questions but only about eighteen…
Two Pointers — Practice Problems
Twelve problems that drill the two-pointer pattern from Lesson 3. The reps are…
Two Pointers
Two pointers is the first pattern to master — it is simple, it appears…