description: You have an array of integers (initially empty).
  
  You have to perform q queries. Each query is of one of two types: 
  
    * "1 x" — add the element x to the end of the array; 
    * "2 x y" — replace all occurrences of x in the array with y. 
  
  
  
  Find the resulting array after performing all the queries.
  
  Input
  
  The first line contains a single integer q (1 ≤ q ≤ 5 ⋅ 10^5) — the number of queries.
  
  Next q lines contain queries (one per line). Each query is of one of two types: 
  
    * "1 x" (1 ≤ x ≤ 5 ⋅ 10^5); 
    * "2 x y" (1 ≤ x, y ≤ 5 ⋅ 10^5). 
  
  
  
  It's guaranteed that there is at least one query of the first type.
  
  Output
  
  In a single line, print k integers — the resulting array after performing all the queries, where k is the number of queries of the first type.
  
  Examples
  
  Input
  
  
  7
  1 3
  1 1
  2 1 2
  1 2
  1 1
  1 2
  2 1 3
  
  
  Output
  
  
  3 2 2 3 2 
  
  Input
  
  
  4
  1 1
  1 2
  1 1
  2 2 2
  
  
  Output
  
  
  1 2 1 
  
  Input
  
  
  8
  2 1 4
  1 1
  1 4
  1 2
  2 2 4
  2 4 3
  1 2
  2 2 7
  
  
  Output
  
  
  1 3 3 7 
  
  Note
  
  In the first example, the array changes as follows:
  
  [] → [3] → [3, 1] → [3, 2] → [3, 2, 2] → [3, 2, 2, 1] → [3, 2, 2, 1, 2] → [3, 2, 2, 3, 2].
  
  In the second example, the array changes as follows:
  
  [] → [1] → [1, 2] → [1, 2, 1] → [1, 2, 1].
  
  In the third example, the array changes as follows:
  
  [] → [] → [1] → [1, 4] → [1, 4, 2] → [1, 4, 4] → [1, 3, 3] → [1, 3, 3, 2] → [1, 3, 3, 7].
solution: import java.io.*;
  import java.util.*;
  
  public class Main {
      public static void main(String[] args) {
          FastIO fio = new FastIO();
  
          int q = fio.nextInt();
          List<Integer> nums = new ArrayList<>();
          Stack<Triple> changes = new Stack<>();
  
          for (int i = 0; i < q; i++) {
              int type = fio.nextInt();
  
              if (type == 1) {
                  nums.add(fio.nextInt());
              } else {
                  changes.push(new Triple(fio.nextInt(), fio.nextInt(), nums.size()));
              }
          }
  
          HashMap<Integer, Integer> map = new HashMap<>();
          int stop = nums.size();
  
          while (!changes.isEmpty()) {
              Triple change = changes.pop();
  
              // Apply previous changes first
              for (int i = change.index; i < stop; i++) {
                  int num = nums.get(i);
  
                  if (map.containsKey(num)) {
                      nums.set(i, map.get(num));
                  }
              }
  
              stop = change.index;
  
              if (map.containsKey(change.y)) {
                  map.put(change.x, map.get(change.y));
              } else {
                  map.put(change.x, change.y);
              }
          }
  
          for (int i = 0; i < stop; i++) {
              int num = nums.get(i);
  
              if (map.containsKey(num)) {
                  nums.set(i, map.get(num));
              }
          }
  
          boolean first = true;
  
          for (int num : nums) {
              if (first) {
                  first = false;
              } else {
                  fio.print(" ");
              }
  
              fio.print(num);
          }
  
          fio.println();
  
          fio.close();
      }
  }
  
  class Triple {
      int x;
      int y;
      int index;
  
      Triple(int x, int y, int index) {
          this.x = x;
          this.y = y;
          this.index = index;
      }
  }
  
  /**
   * Fast I/O
   * @source https://www.geeksforgeeks.org/fast-io-in-java-in-competitive-programming/
   */
  class FastIO extends PrintWriter 
  { 
      BufferedReader br; 
      StringTokenizer st;
  
      public FastIO() 
      { 
          super(new BufferedOutputStream(System.out)); 
          br = new BufferedReader(new
                  InputStreamReader(System.in));
      } 
  
      String next() 
      { 
          while (st == null || !st.hasMoreElements()) 
          { 
              try
              { 
                  st = new StringTokenizer(br.readLine()); 
              } 
              catch (IOException  e) 
              { 
                  e.printStackTrace(); 
              } 
          } 
          return st.nextToken(); 
      } 
  
      int nextInt() 
      { 
          return Integer.parseInt(next()); 
      } 
  
      long nextLong() 
      { 
          return Long.parseLong(next()); 
      } 
  
      double nextDouble() 
      { 
          return Double.parseDouble(next()); 
      } 
  
      String nextLine() 
      { 
          String str = ""; 
          try
          { 
              str = br.readLine(); 
          } 
          catch (IOException e) 
          { 
              e.printStackTrace(); 
          } 
          return str; 
      } 
  }
  
  