[LeetCode] Sqrt(x)

 1 class Solution {
 2 public:
 3     int sqrt(int x) {
 4         int low = 1;
 5         int high = x / 2;
 6         int mid, ans;
 7         
 8         if (x < 2) return x;
 9         
10         while (low <= high) {
11             mid = low + (high - low) / 2;
12             if (mid <= x / mid) {
13                 low = mid + 1;
14                 ans = mid;
15             } else {
16                 high = mid - 1;
17             }
18         }
19         
20         return ans;
21     }
22 };