青蛙的约会 java版

参考http://blog.csdn.net/polossk/article/details/9799735

package acm;

public class FrogDate {

    public static void main(String[] args) {

        int x = ,y = ,m = ,n = ,l = ;
        int ar=n-m,br=,cr=x-y;
        int M = exGcd(n-m,l,ar,br);

        System.out.println("M:" + M);

        if((x-y)%M!= || m==n)
            System.out.println("Impossible");
        else{
            int s=l/M;
            ar=ar*((x-y)/M);              ar=(ar%s+s)%s;
            System.out.println("ar : " + ar);
        }
    }

    static int Gcd(int a, int b)
    {
        while(b != )
        {
            int r = b;
            b = a % b;
            a = r;
        }
        return a;
    }

    static int exGcd(int a, int b, int x, int y)
    {
        if(b == )
        {
            x = ;
            y = ;
            return a;
        }
        int r = exGcd(b, a % b, x, y);
        int t = x;
        x = y;
        y = t - a / b * y;
        return r;
    } 

}