代码
利用二分法
class Solution {
public:
int sqrt(int x) {
long long i = 0;
long long j = x/2+1;
while(i<=j)
{
long long mid = (i+j)/2;
long long temp = mid*mid;
if(temp==x)
return mid;
else if(temp>x)
j = mid - 1;
else
i = mid + 1;
}
return j;
}
};