[leetcode刷题系列]Sqrt(x)

二分就好了

class Solution {public:    int sqrt(int x) {        // Start typing your C/C++ solution below        // DO NOT write int main() function        if(x <= 0)            return 0;        long long low = 1, high = x, mid;        while(low <= high){            mid = low + high >> 1;            if(mid * mid > x)                high = mid - 1;            else                low = mid + 1;        }        return low - 1;    }};