u010217031的博客

451. Sort Characters By Frequency 1、原题 Given a string, sort it in decreasing order based on the frequency of characters. 2、题目意思及思考解析 题目意思很简单，就是给你一个字符串，根据其字符出现的频率对其重新排序；频率高的排在前面，相同频率的排序不限。如“t

Length of Last Word 1、原题 Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string. If the last word does not

31. Next Permutation 一、原题 Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers. If such arrangement is not possible, it must rea

110. Balanced Binary Tree 1、原题 Given a binary tree, determine if it is height-balanced. For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the t

141. Linked List Cycle 1、原题 Given a linked list, determine if it has a cycle in it. Follow up: Can you solve it without using extra space? 2、题意解析与思路 这道题就是让我们判断一个链表中存不存在环的问题。这个问题比较简

50. Pow(x, n) 1、原题 Implement pow(x, n). Subscribe to see which companies asked this question. 2、题意解析 这道题的题意很是简单，就是让我们实现pow(x,n)这个函数。 一开始，我想到的是最简单的循环累乘，在这里我们会发现这样超时。因此要改变我们的思路。             我后面

34. Search for a Range 一、原题 Given an array of integers sorted in ascending order, find the starting and ending position of a given target value. Your algorithm's runtime complexity must be

20. Valid Parentheses 1、原题 Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. The brackets must close in the correct or

515. Find Largest Value in Each Tree Row 1、原题 You need to find the largest value in each row of a binary tree. Example: Input: 1 / \ 3 2 / \ \

137. Single Number II 1、原题 Given an array of integers, every element appears three times except for one, which appears exactly once. Find that single one. 2、题目解析与思路 这道题是从Single NumberI发展

11. Container With Most Water 1、原题 Given n non-negative integers a1, a2, ..., an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints

Convert BST to Greater Tree 1、原题 Given a Binary Search Tree (BST), convert it to a Greater Tree such that every key of the original BST is changed to the original key plus sum of all keys greate

15. 3Sum 1、原题 Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero. 2、解读与思路 这道题目的意

Longest Substring Without Repeating Characters 1、原题 Given a string, find the length of the longest substring without repeating characters. 2、题目解析及分析 题目一目了然，很简单，让我们一遍找到一个字符串的最小子串。 首先，这道题

482. License Key Formatting 1、原题： Now you are given a string S, which represents a software license key which we would like to format. The string S is composed of alphanumerical characters and

ZigZag Conversion 1、原题 The string "PAYPALISHIRING" is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibili

Single Number 1、原题 Given an array of integers, every element appears twice except for one. Find that single one. Note: Your algorithm should have a linear runtime complexity. Could you imple

59. Spiral Matrix II 1、原题 Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order. For example, Given n = 3, You should return the following matrix: