LeetCode 69. Sqrt(x)

#include <vector>
#include <iostream>
using namespace std;

int sqrt(int x) {
long long left = 0;
long long right = x;
long long xx = x;
while(left < right) {
long long mid = (left + right) / 2;
if(mid * mid <= xx && (mid + 1)* (mid + 1) > xx) {return (int) mid;}
if(mid * mid < xx) left = mid + 1;
else if(mid * mid > xx) right = mid - 1;
}
}

int main(void) {
int sq = sqrt(4);
cout << sq << endl;
}