qwe_lingkun的专栏

题目12： Given an integer, convert it to a roman numeral. Input is guaranteed to be within the range from 1 to 3999. /****************************************************************************

题目191： Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight). For example, the 32-bit integer ’11' has binary representation

Given two binary trees, write a function to check if they are equal or not. Two binary trees are considered equal if they are structurally identical and the nodes have the same value. /** * Def

Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array. Note: You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold add

把一个数组最开始的若干个元素搬到数组的末尾，我们称之为数组的旋转。输入一个递增排序的数组的一个旋转，输出旋转数组的最小元素。例如数组{3,4,5,1,2}为{1,2,3,4,5}的一个旋转，该数组的最小值为1。 public : int BinarySearch(vector arr, int start, int end) { int i = 0;

题目9： Determine whether an integer is a palindrome. Do this without extra space. Some hints: Could negative integers be palindromes? (ie, -1) If you are thinking of converting the integer to st

题目8： Implement atoi to convert a string to an integer. Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible inpu

题目5： Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000, and there exists one unique longest palindromic substring. /***************

题目4： There are two sorted arrays nums1 and nums2 of size m and n respectively. Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)). /******************

题目13： Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999. int StrLen(char* s) { int l = 0; while (*s++ != 0) { l++;

题目3： Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters for "abcabcbb" is "abc", which the length is 3

题目6： 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 legibility) P A H N

题目14： Write a function to find the longest common prefix string amongst an array of strings. 在一组字符串中，查找最长的公共前缀，并输出。 从第一个字符，依次遍历所有字符串，如果第一个字符都相同，则添加到结果中； 直到遍历到不同字符，或某一字符串遍历结束，则输出结果。 char* max_pr

题目15： 代码写的非常复杂和凌乱，需要再进行整理。 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. Note:

题目136： 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 implement it without

题目1： Given an array of integers, find two numbers such that they add up to a specific target number. The function twoSum should return indices of the two numbers such that they add up to the target,

题目11： 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 of line i is at (i, ai) and (i,

题目2： You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as

题目10： （该题目拿到手没什么特别好的思路，从网上看的别人的解法，然后写了下自己的理解，需要常回顾） Implement regular expression matching with support for '.' and '*'. '.' Matches any single character. '*' Matches zero or more of the preceding

题目7： Reverse digits of an integer. Example1: x = 123, return 321 Example2: x = -123, return -321 click to show spoilers. Have you thought about this? Here are some good questions to as