Basic simulation. Just need to follow the instructions in the question.

import java.awt.Point;
import java.util.ArrayList;
import java.util.Scanner;

/**
 * 
 * @author Sanchit M. Bhatnagar
 * @see http://uhunt.felix-halim.net/id/74004
 * 
 */
public class P101 {

  public static void main(String args[]) // entry point from OS
  {
    Scanner sc = new Scanner(System.in);
    int size = sc.nextInt();
    @SuppressWarnings("unchecked")
    ArrayList<Integer>[] blocks = new ArrayList[size];
    for (int i = 0; i < size; i++) {
      blocks[i] = new ArrayList<Integer>();
      blocks[i].add(i);
    }

    // System.out.println(Arrays.deepToString(blocks));

    while (sc.hasNext()) {
      String t = sc.next();
      if (t.equals("quit")) {
        break;
      } else {
        int a = sc.nextInt();
        String x = sc.next();
        int b = sc.nextInt();

        if (a == b)
          continue;

        Point posA = findBlock(a, blocks);
        Point posB = findBlock(b, blocks);

        if (posA.x == posB.x)
          continue;

        if (t.equals("move")) {
          moveBack(posA, blocks);
          if (x.equals("onto")) {
            moveBack(posB, blocks);
            blocks[posA.x].remove(posA.y);
            blocks[posB.x].add(a);
          } else {
            blocks[posA.x].remove(posA.y);
            blocks[posB.x].add(a);
          }
        } else if (t.equals("pile")) {
          if (x.equals("onto")) {
            moveBack(posB, blocks);
            int removed = 0;
            int tSize = blocks[posA.x].size();
            for (int i = posA.y; i < tSize; i++) {
              blocks[posB.x].add(blocks[posA.x].remove(i - removed));
              removed++;
            }
          } else {
            int removed = 0;
            int tSize = blocks[posA.x].size();
            for (int i = posA.y; i < tSize; i++) {
              blocks[posB.x].add(blocks[posA.x].remove(i - removed));
              removed++;
            }
          }
        }
      }
      // System.out.println(Arrays.deepToString(blocks));
    }

    // System.out.println(Arrays.deepToString(blocks));

    for (int i = 0; i < size; i++) {
      System.out.print(i + ":");
      int tSize = blocks[i].size();
      for (int j = 0; j < tSize; j++) {
        System.out.print(" " + blocks[i].remove(0));
      }
      System.out.println();
    }
    sc.close();
  }

  private static void moveBack(Point posA, ArrayList<Integer>[] blocks) {
    int removed = 0;
    int tSize = blocks[posA.x].size();
    for (int i = posA.y + 1; i < tSize; i++) {
      int x = (Integer) blocks[posA.x].remove(i - removed);
      removed++;
      blocks[x].add(x);
    }
  }

  private static Point findBlock(int a, ArrayList<Integer>[] blocks) {
    for (int i = 0; i < blocks.length; i++) {
      for (int j = 0; j < blocks[i].size(); j++) {
        if ((Integer) blocks[i].get(j) == a) {
          return new Point(i, j);
        }
      }
    }
    return null;
  }
}

So this question is interesting. I was updating too much and was getting TLE. Once a buddy dies, there are obviously no more requests containing army members who are no more. We can therefore safely update only the end points of every given query.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;

/**
 * 
 * @author Sanchit M. Bhatnagar
 * @see http://uhunt.felix-halim.net/id/74004
 * 
 */
public class P12356 {

  public static void main(String[] args) throws NumberFormatException, IOException {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    PrintWriter out = new PrintWriter(System.out);
    StringTokenizer st = null;

    String line = null;
    while ((line = br.readLine()) != null) {
      st = new StringTokenizer(line);
      int S = Integer.parseInt(st.nextToken());
      int B = Integer.parseInt(st.nextToken());
      if (S == 0 && B == 0)
        break;
      int[] leftBuddy = new int[S + 2];
      int[] rightBuddy = new int[S + 2];
      for (int i = 1; i <= S; i++) {
        leftBuddy[i] = i - 1;
        rightBuddy[i] = i + 1;
      }
      rightBuddy[S] = 0;
      for (int i = 0; i < B; i++) {
        st = new StringTokenizer(br.readLine());
        int l = Integer.parseInt(st.nextToken());
        int r = Integer.parseInt(st.nextToken());
        if (leftBuddy[l] == 0)
          out.print("* ");
        else
          out.print(leftBuddy[l] + " ");
        if (rightBuddy[r] == 0)
          out.println("*");
        else
          out.println(rightBuddy[r]);
        leftBuddy[rightBuddy[r]] = leftBuddy[l];
        rightBuddy[leftBuddy[l]] = rightBuddy[r];
      }
      out.println("-");
    }
    out.close();
    br.close();
  }
}