【POJ-1061 青蛙的约会】

题目

代码

#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
LL ex_gcd(LL a, LL b, LL &x, LL &y)
{if (b == 0){x = 1;y = 0;return a;}LL gcd = ex_gcd(b, a % b, x, y);LL tmp = x;x = y;y = tmp - a / b * y;return gcd;
}
int main()
{LL x, y, m, n, l;cin >> x >> y >> m >> n >> l;LL a = n - m, b = l, c = x - y;LL X, Y;LL gcd = ex_gcd(a, b, X, Y);if (c % gcd){cout << "Impossible";return 0;}X = X * c / gcd;b /= gcd;if (b < 0)b = -b;X = (X % b + b) % b;cout << X;return 0;
}