Grasshopper.java

 
import java.io.BufferedReader;
 
/*
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 * and open the template in the editor.
 */
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
 
 
 
/**
 *
 * @author cteam022
 */
public class Grasshopper {
 
    BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
 
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws IOException {
        Grasshopper g = new Grasshopper();
        while(true){g.uloha();}
    }
 
    void uloha() throws IOException{
        if(!input.ready()){System.exit(0);}
        st = new StringTokenizer(input.readLine());
        int a = Integer.valueOf(st.nextToken());
        int b = Integer.valueOf(st.nextToken());
        int x1 = Integer.valueOf(st.nextToken());
        int y1 = Integer.valueOf(st.nextToken());
        int x2 = Integer.valueOf(st.nextToken());
        int y2 = Integer.valueOf(st.nextToken());
 
        int x = x1, y = y1;
 
        int i;
 
        for(i=0; Math.abs(x - x2) > 2 && Math.abs(y - y2)>2; i++){
            int dx = x2 - x;
            int dy = y2 - y;
 
            if(Math.abs(dx) >= Math.abs(dy)){
                x += Math.signum(dx)*2;
                y += Math.signum(dy);
            }else{
                x += Math.signum(dx);
                y += Math.signum(dy)*2;
            }
        }
 
        int p = rekurze(6, x2, y2, x, y, a, b);
 
        if(p == 100){
            System.out.println("impossible");
        }else{
            System.out.println(i+p);
        }
 
    }
 
    static int rekurze(int pocet, int x2, int y2, int x,int y,int a, int b){
        if (pocet < 0) return 100;
        if (x2 == x && y2 == y) return 0;
        int min = 100;
        for(int druhx = -1; druhx < 2; druhx+=2){           
            for(int druhy = -1; druhy < 2; druhy+=2){
                if(x+druhx*2 < a && x+druhx*2>=0 && y+druhy < b && y+druhy >=0){
                    int r1 = rekurze(pocet - 1, x2, y2, x+druhx*2, y+druhy, a, b); 
                    min = Math.min(r1, min);
                }
                if(x+druhx < a && x+druhx>=0 && y+druhy*2 < b && y+druhy*2 >=0){
                    int r2 = rekurze(pocet - 1,x2, y2, x+druhx, y+druhy*2, a, b); 
                    min = Math.min(r2, min);
                }
            }
 
        }   
        return min==100 ? 100 : min + 1;
    }
 
}