Problem:
Extended Euclid Algorithm

Given positive integers a and b, find the integer solution (x, y) to ax + by = gcd(a, b), where gcd(a, b) is the greatest common divisor of a and b.

Input

a b

Two positive integers a and b are given separated by a space in a line.

Output

Print two integers x and y separated by a space. If there are several pairs of such x and y, print that pair for which |x| + |y| is the minimal (primarily) and x ≤ y (secondarily).

Constraints

1 ≤ a, b ≤ 109

Sample Input 1

4 12

Sample Output 1

1 0

Sample Input 2

3 8

Sample Output 2

3 -1

Solution in C# (judge verdict: Accepted)

using System;

public class Hello
{
    public static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var a = int.Parse(line[0]);
        var b = int.Parse(line[1]);
        var x = 1;
        var y = 1;
        extgcd(a, b, ref x, ref y);
        Console.WriteLine("{0} {1}", x, y);
    }
    public static int extgcd(int a, int b, ref int x, ref int y)
    {
        var d = a;
        if (b != 0)
        {
            d = extgcd(b, a % b, ref y, ref x);
            y -= (a / b) * x;
        }
        else { x = 1; y = 0; }
        return d;
    }
}