101 - The Blocks Problem

main.java

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


public class Main {	
	
	private static Stack[] Blocks;
	private static PrintWriter out;
	
	public static void main(String[] args) throws Exception {
		Scanner in = new Scanner(System.in);
		out = new PrintWriter(System.out, true);

		
		
		// read first line
		int items = Integer.valueOf(in.nextLine());
		
		Blocks = new Stack[items];
		
		
		
		for (int i = 0; i < items; i++) {
			Blocks[i] = new Stack<Integer>();
			Blocks[i].push(i);
		}
		
		
		String Line = "";
		
		// Do a loop thing
		while(!(Line = in.nextLine()).equals("quit")) {
			  	String[]Splited = Line.split("\\s+");
			  	
			  	
			  	
			  	
			  	Integer a = Integer.valueOf(Splited[1]); 
			  	Integer b = Integer.valueOf(Splited[3]);
			  	
			  	if (findPosition(a) != findPosition(b)){
			  
				  	if (Splited[0].trim().equals("move")) {
				  		if (Splited[2].trim().equals("onto"))
				  			moveOnto(a,b);
				  		if (Splited[2].trim().equals("over"))
				  			moveOver(a,b);
				  	}
				  	
				  	if (Splited[0].trim().equals("pile")) {
				  		if (Splited[2].trim().equals("onto"))
				  			pileOnto(a,b);
				  		if (Splited[2].trim().equals("over"))
				  			pileOver(a,b);
				  	}
				  
			  	}
			  
		  }
		
		for (int i = 0; i < items; i++) {
			String item = "";
			
			Stack<Integer> Tom = Blocks[i];
			
			for (Integer el : Tom) {
				item = item + " " + el; 
			}
			out.printf(i + " :" + item + "\n");
			
		}
	}
	
	
	public static void moveOnto(Integer a, Integer b) {
		// clear any block on top of a back to their original position
		clearAbove(b);
		
		// same as moveOver
		moveOver(a, b);
	}
	
	
	public static void moveOver(Integer a, Integer b) {
		// put all blocks above b back into their original position
		clearAbove(a);
		
		// move block a onto top of stack containing b
		Blocks[findPosition(b)].push(Blocks[findPosition(a)].pop());
	}
	
	public static void pileOnto(Integer a, Integer b) {
		// move blocks on top of b to their original position
		clearAbove(b);
		
		// same as pileOver
		pileOver(a, b);
	}
	
	public static void pileOver(Integer a, Integer b) {
		// move all blocks above a and including a onto the top of stack containing b
		
		Stack<Integer> currentBlock = Blocks[findPosition(a)];
		Stack<Integer> moveToBlock = Blocks[findPosition(b)];
		
		for (Integer i = findIndex(a); i < currentBlock.size(); i++) {
			Integer item = currentBlock.get(i);
			moveToBlock.push(item);
		}
	}

	public static void clearAbove(Integer a) {
		Stack<Integer> currentBlock = Blocks[findPosition(a)];
		
		for (Integer i = findIndex(a) + 1; i < currentBlock.size(); i++) {
			// Get item and add it to original block position
			Integer item  = currentBlock.get(i);
			Blocks[item].push(item);
			
			currentBlock.remove(i); // Remove item
		}
	}
	
	public static  Integer findPosition(Integer a) {
		for (Integer i = 0; i < Blocks.length; i++) {
			if (Blocks[i].contains(a)){
				return i;
			}
		}
		return -1;
	}
	
	public static Integer findIndex(Integer a) {
		return Blocks[findPosition(a)].indexOf(a);
	}
}