Leetcode 130: Surrounded Regions
Given a 2D board containing ‘X’ and ‘O’ (the letter O), capture all regions surrounded by ‘X’.
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Leetcode 129: Sum Root to Leaf Numbers
Question Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number. [Read More] -
Leetcode 146: LRU Cache
Question Design and implement a data structure for Least Recently Used (LRU) cache. It should support the following operations: get and put. [Read More] -
Leetcode 680: Valid Palindrome II
Question Given a non-empty string s, you may delete at most one character. Judge whether you can make it a palindrome. [Read More] -
Leetcode 125: Valid Palindrome
Question Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. [Read More] -
Leetcode 122: Best Time to Buy and Sell Stock II
Question Say you have an array for which the ith element is the price of a given stock on day i. [Read More] -
Leetcode 121: Best Time to Buy and Sell Stock
Question Say you have an array for which the ith element is the price of a given stock on day i. [Read More] -
Leetcode 120: Triangle
Question Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on the row below. [Read More] -
Leetcode 119: Pascal's Triangle II
Question Given a non-negative index k where k ≤ 33, return the \(k^{th}\) index row of the Pascal’s triangle. [Read More] -
Leetcode 117: Populating Next Right Pointers in Each Node II
Question Given a binary tree struct TreeLinkNode { TreeLinkNode *left; TreeLinkNode *right; TreeLinkNode *next; } [Read More] -
Leetcode 116: Populating Next Right Pointers in Each Node
Question Given a binary tree struct TreeLinkNode { TreeLinkNode *left; TreeLinkNode *right; TreeLinkNode *next; } [Read More] -
Leetcode 118: Pascal's Triangle
Question Given a non-negative integer numRows, generate the first numRows of Pascal’s triangle. [Read More] -
Leetcode 114: Flatten Binary Tree to Linked List
Question Given a binary tree, flatten it to a linked list in-place. [Read More] -
Leetcode 437: Path Sum III
Question You are given a binary tree in which each node contains an integer value. [Read More] -
Leetcode 113: Path Sum II
Question Given a binary tree and a sum, find all root-to-leaf paths where each path’s sum equals the given sum. [Read More]