codeforce 7C
C. Line
time limit per test1 second
memory limit per test256 megabytes
A line on the plane is described by an equation Ax + By + C = 0. You are to find any point on this line, whose coordinates are integer numbers from - 5·1018 to 5·1018 inclusive, or to find out that such points do not exist.
Input
The first line contains three integers A, B and C ( - 2·109 ≤ A, B, C ≤ 2·109) — corresponding coefficients of the line equation. It is guaranteed that A2 + B2 > 0.
Output
If the required point exists, output its coordinates, otherwise output -1.
Examples
input
2 5 3
output
6 -3
代码如下:
#include <iostream>
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;
}
int ans = ex_gcd(b,a%b,x,y);
int tmp = x;
x = y;
y = tmp - a/b * y;
return ans;
}
int main()
{
ll x, y;
ll a, b, c;
cin >> a >> b >> c;
c *= -1;
ll gcd = ex_gcd(a,b,x,y);
if(c%gcd)
{
cout << "-1" << endl;
}
else
{
int k = c/gcd;
x *= k;
y *= k;
cout << x << " " << y << endl;
}
return 0;
}
扩展欧几里得算法