leetcode——69——Sqrt(x)

Implement int sqrt(int x).

Compute and return the square root of x.

考虑到不是完全平方数的情况

class Solution {public:    int mySqrt(int x) {        if(x <= 0) return 0;        int low = 1;        int high = x;        int mid;        while (low <= high) {                        mid = (high + low)/ 2;                        if ((x / mid >= mid) && ((mid + 1) > x / (mid + 1))) { //to avoid overflow                return mid;             } else if ( x / mid < mid ) {                high = mid - 1;            } else {                low = mid + 1;            }                    }        return -1;    }};