leetcode 69和367

69. Sqrt(x)

代码：

class Solution {
public:int mySqrt(int x) {int left = 0;int right = x;long long mid = 0;int res = 0;long long temp = 0;while(left <= right){mid = left + ((right - left)>>1);temp = mid*mid;if(temp == x){res = mid;break;}else if(temp > x){right = mid -1;}else{left = mid + 1;}}if(left > right)res = right;return res;}
};

 367. Valid Perfect Square

代码：

class Solution {
public:bool isPerfectSquare(int num) {int left = 1;int right = num;long long mid = 0;long long temp = 0;while(left <= right){mid = left + ((right - left)>>1);temp = mid*mid;if(temp == num)return true;else if(temp > num){right = mid -1;}else{left = mid +1;}}return false;}
};