Medium
Palindromic Substrings
Palindromic Substrings
Senior StaffTwo PointersStringDynamic Programming
LeetCode Journal
Technical walkthroughs and complexity analysis of competitive programming problems.
Medium
Longest Palindromic Substring
Given a string s, return the longest palindromic substring in s.
Two PointersStringDynamic Programming
Medium
Longest Substring Without Repeating Characters
Given a string s, find the length of the longest substring without repeating characters.
StaffHash TableStringSliding Window
Medium
Clone Graph
Given a reference of a node in a connected undirected graph, return a deep copy (clone) of the graph.
Hash TableDepth-First SearchBreadth-First SearchGraph Theory
Medium
Longest Consecutive Sequence
Given an unsorted array of integers, find the length of the longest consecutive elements sequence in O(n) time.
ArrayHash TableSet
Easy
Two Sum
Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.
JuniorArrayHash Table