LeetCode 69. Sqrt(x)

题意

求n√

思路

使用二分法求解，其中注意，mid∗mid有可能会int溢出.

代码

class Solution {public:    int mySqrt(int x) {        if(x <= 0) return 0;        int l = 1, r = x;        while(l < r){            int mid = (l + r + 1) / 2;            if(mid > x / mid){                r = mid - 1;            } else{                l = mid;            }        }        return l;    }};