dihedral.java

Ulm大学2005-2006年竞赛题

import java.io.*;
import java.util.*;

public class dihedral {
	public static void main(String [] args) throws Exception {
		Scanner in = new Scanner(new File("dihedral.in"));
		int n;
		while( (n = in.nextInt()) != 0) {
			int sign = 1;
			int rotation = 0;
			while(!in.hasNextInt()) {
				String s = in.next();
				int v = Integer.parseInt(s.substring(1));
				if (s.charAt(0) == 'm') {
					v %= 2;
					if (v != 0)
						sign = -sign;
				}
				else {
					rotation += sign*v;
					rotation %= n;
				}
			}
			if (rotation < 0)
				rotation += n;
			if (sign < 0) {
				if (n-rotation < rotation)
					System.out.println("m1 r"+(n-rotation));
				else if (rotation > 0)
					System.out.println("r"+rotation+" m1");
				else
					System.out.println("m1");
			}
			else {
				if (n-rotation+2<rotation)
					System.out.println("m1 r"+(n-rotation)+" m1");
				else
					System.out.println(rotation>0?"r"+rotation:"");
			}
		}
	}
}