LeetCode69题

public static int mySqrta(int x) {
        int left = 0;
        int right = x;
        int ans = -1;
        int mid = left + (right - left) / 2;
        while (left <= right) {

            if ((long) mid * mid <= x) {
                ans = mid;
                left = mid + 1;
            } else {
                right = mid - 1;
            }
        }
        return ans;
    }