Contains Duplicate Given an array of integers, find if the array contains any duplicates. Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct. 解题思路 用一个set保存数组中的值,假…

Contains Duplicate II Given an array of integers and an integer k, find out whether there there are two distinct indices i and j in the array such that nums[i] = nums[j] and the difference between i and j is at most k. Have you met this question in a…

Given an array of integers and an integer k, return true if and only if there are two distinct indices i and j in the array such that nums[i] = nums[j] and the difference between i and j is at most k. (Old Version) Given an array of integers and an i…

SingleNumber I: 题目链接:https://leetcode-cn.com/problems/single-number/ 题意: 给定一个非空整数数组,除了某个元素只出现一次以外,其余每个元素均出现两次.找出那个只出现了一次的元素. 说明: 你的算法应该具有线性时间复杂度. 你可以不使用额外空间来实现吗? 示例 1: 输入: [2,2,1] 输出: 1 示例 2: 输入: [4,1,2,1,2] 输出: 4 分析: 利用异或(xor)运算,两个相同的数异或为0 代码如下: cla…

题意:如果有两个相同的元素,它们之间的距离不超过k,那么返回true,否则false. 思路:用map记录每个出现过的最近的位置,扫一边序列即可.扫到一个元素就判断它在前面什么地方出现过.本题数据有点弱. class Solution { public: bool containsNearbyDuplicate(vector<int>& nums, int k) { if(nums.empty()) return false; unordered_map<int,int>…

Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the difference between i and j is at most k. class Solution: # @param {integer[]} nums # @param {integer…

Array Hash Table Description: Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the absolute difference between i and j is at most k. 本来继续沿用I里的HashSet,奈何用…

Description: Given an array of integers and an integer k, find out whether there there are two distinct indices i and j in the array such that nums[i] = nums[j] and    the difference between i and j is at most k   public class Solution { public boole…

Given an array of integers, find out whether there are two distinct indices i and j in the array such that the difference between nums[i] and nums[j] is at most t and the difference between i and j is at most k. 这道题跟之前两道Contains Duplicate 包含重复值和Conta…

[1]LeetCode 136 Single Number 题意:奇数个数,其中除了一个数只出现一次外,其他数都是成对出现,比如1,2,2,3,3...,求出该单个数. 解法:容易想到异或的性质,两个相同的数异或为0,那么把这串数从头到尾异或起来,最后的数就是要求的那个数. 代码如下: class Solution { public: int singleNumber(vector<int>& nums) { ; ;i<nums.size();i++) sum ^= nums[i…