Given an array nums containing n + 1 integers where each integer is between 1 and n (inclusive), prove that at least one duplicate element must exist. Assume that there is only one duplicate number, find the duplicate one. Note: You must not modify t…

Given an array nums containing n + 1 integers where each integer is between 1 and n (inclusive), prove that at least one duplicate number must exist. Assume that there is only one duplicate number, find the duplicate one. Example 1: Input: [1,3,4,2,2…

一个长度为 n + 1 的整形数组,其中的数字都在 1 到 n 之间,包括 1 和 n ,可知至少有一个重复的数字存在.假设只有一个数字重复,找出这个重复的数字.注意:    不能更改数组内容(假设数组是只读的).    只能使用恒定的额外空间,即要求空间复杂度是 O(1) .    时间复杂度小于 O(n2)    数组中只有一个数字重复,但它可能不止一次重复出现.详见:https://leetcode.com/problems/find-the-duplicate-number/descri…

Leetcode之二分法专题-287. 寻找重复数(Find the Duplicate Number) 给定一个包含 n + 1 个整数的数组 nums,其数字都在 1 到 n 之间(包括 1 和 n),可知至少存在一个重复的整数.假设只有一个重复的整数,找出这个重复的数. 示例 1: 输入: [1,3,4,2,2] 输出: 2 示例 2: 输入: [3,1,3,4,2] 输出: 3 说明: 不能更改原数组(假设数组是只读的). 只能使用额外的 O(1) 的空间. 时间复杂度小于 O(n2)…

Description: Given an array nums containing n + 1 integers where each integer is between 1 and n (inclusive), prove that at least one duplicate number must exist. Assume that there is only one duplicate number, find the duplicate one. Note: You must…

最容易想到的思路是新开一个长度为n的全零list p[1~n].依次从nums里读出数据,假设读出的是4, 就将p[4]从零改成1.如果发现已经是1了,那么这个4就已经出现过了,所以他就是重复的那个数.这个解法的时间复杂度是O(N).但是由于本题要求空间复杂度是O(1).所以不能用. 可以用二分法,low = 1, high = n, mid = (left + right)//2,如果<=mid 的元素个数 > mid,那么重复的数字一定在[1, mid]区间内.反之,则一定在[mid+1,…

题意: 有一个含有n+1个元素的数组,元素值是在1-n之间的整数,请找出其中出现超过1次的数.(保证仅有1个出现次数是超过1的数) 思路: 方法一:O(nlogn).根据鸽笼原理及题意,每次如果<=k的数超过了k个,那么答案必定在[1,k].可以用二分枚举答案来解决. bool left(vector<int>& nums,int tar)//是否在左边 { ; ; i<nums.size(); i++) if(nums[i]<=tar) cnt++; return…

Given an array nums containing n + 1 integers where each integer is between 1 and n (inclusive), prove that at least one duplicate number must exist. Assume that there is only one duplicate number, find the duplicate one. Example 1: Input: [1,3,4,2,2…

Given an array nums containing n + 1 integers where each integer is between 1 and n (inclusive), prove that at least one duplicate number must exist. Assume that there is only one duplicate number, find the duplicate one. Note: You must not modify th…

Difficulty:medium  More:[目录]LeetCode Java实现 Description Given an array nums containing n + 1 integers where each integer is between 1 and n(inclusive), prove that at least one duplicate number must exist. Assume that there is only one duplicate numbe…