# 分类：LeetCode题目解答汇总

## LeetCode | First Missing Positive（第一个缺失的正整数）

Given an unsorted integer array, find the first missing positive integer. For example, Given [1,2,0] …

## LeetCode | Reverse Nodes in k-Group（k个结点一组翻转链表）

Given a linked list, reverse the nodes of a linked list k at a time and return its modified list. If…

## LeetCode | Single Number II（单个数字II）

Given an array of integers, every element appears three times except for one. Find that single one. …

## LeetCode | Sort Colors（荷兰国旗问题）

Given an array with n objects colored red, white or blue, sort them so that objects of the same colo…

## LeetCode | Surrounded Regions（包围的区域）

Given a 2D board containing 'X' and 'O', capture all regions surrounded by 'X'. A region i…

## LeetCode | Triangle（三角形路径和）

Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on …

## LeetCode | Gas Station（加油站）

There are N gas stations along a circular route, where the amount of gas at station i is&n…

## LeetCode | Path Sum II（路径和2）

Given a binary tree and a sum, find all root-to-leaf paths where each path’s sum equals the given sum. F…

## LeetCode | Letter Combinations of a Phone Number（号码的字符串组合）

Given a digit string, return all possible letter combinations that the number could represent. A mapping of di…

## LeetCode | Spiral Matrix II（螺旋矩阵填充数据）

Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.…