Leetcode-69 Sqrt(x)

题目介绍

Implement int sqrt(int x).

Compute and return the square root of x.

解决方法

int sqrt(int x) {
if (0 == x) return 0;
int left = 1, right = x, ans;
while (left <= right) {
int mid = left + (right - left) / 2;
if (mid <= x / mid) {
left = mid + 1;
ans = mid;
} else {
right = mid - 1;
}
}
return ans;
}

注意：

若判断mid*mid<=x可能会发生溢出，所以使用mid <= x / mid