Minimize Abs 2.cpp

#include<bits/stdc++.h>
using namespace std;

int main() {
	long long D;
	cin >> D;
	long long resp = D; // resposta comeca sendo D

	for(long long x = 0; x <= ceill(sqrtl(D)); x++) {
		if(D - x*x <= 0) {
			resp = min(resp,abs(D-x*x));
		}
		else {
			long long y1 = floorl(sqrtl(D-x*x));
			long long y2 = ceill(sqrtl(D-x*x));

			resp = min(resp,abs(D-x*x-y1*y1));
			resp = min(resp,abs(D-x*x-y2*y2));
		}
	}

	cout << resp << endl;
}