题解 | #求平方根#

class Solution {
public:
    /**
     * 
     * @param x int整型 
     * @return int整型
     */
    int mysqrt(int x) {
        // write code here
        int left = 0, right = 46342;
        while(left < right) {
            int mid = (left + right) / 2;
            long long y = mid * mid;
            if(y < x)
                left = mid + 1;
            else
                right = mid;
        }
        long long y = left * left;
        if(y <= x)
            return left;
        else
            return left - 1;
    }
};