[백준] 1072 / 게임

#include<iostream>
using namespace std;
using int64 = int64_t;
int64 X = 0;
int64 Y = 0;
int64 Z = 0;
bool test(int64 win)//win 몇판 더이겼는지
{
	int z = ((100 * (Y + win)) / (X + win));
	return Z < z;
}
int main() {
	cin >> X;
	cin >> Y;
	Z = ((100 * Y) / X);
	if (99 <= Z) {
		cout << -1 << '\n';
		return 0;
	}
	int64 s = 0;
	int64 e = X+1;
	int64 mid;
	int64 ret = -1;
	while (s<e)
	{
		mid = (s + e) / 2;
		if (test(mid))
		{
			ret = mid;
			e = mid;
		}
		else
		{
			s = mid + 1;
		}
	}
	
	cout << ret << '\n';
}