目录

一、题目

二、暴力求解

三、二分查找（改进）

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一、题目

https://leetcode.cn/problems/sqrtx/description/

二、暴力求解

1.溢出问题

2.x为1

class Solution {
public:int mySqrt(int x) {if(x== 1)return 1;long long i=0;for(i;i<=x/2;i++){if(i*i>x){break;}}return i-1;}
};

三、二分查找（改进）

class Solution {
public:int mySqrt(int x) {if(x== 0)return 0;if(x== 1||x==2)return 1;long long left=0;long long right = x/2;long long mid = (right+left)/2;while(left<=right){if(mid*mid<x){left = mid+1;mid = (left+right)/2;}else if(mid*mid>x){right = mid-1;mid = (left+right)/2;}else{return mid;}}return right;}
};