public static int quickestWayUp(
    List<List<Integer>> ladders, List<List<Integer>> snakes) {
  int[] board = new int[101];

  for (int i = 0; i < 101; i++) {
    board[i] = i;
  }

  for (List<Integer> ladder : ladders) {
    board[ladder.get(0)] = ladder.get(1);
  }

  for (List<Integer> snake : snakes) {
    board[snake.get(0)] = snake.get(1);
  }

  Queue<int[]> queue = new LinkedList<>();
  boolean[] visited = new boolean[101];
  queue.offer(new int[] {1, 0});

  while (!queue.isEmpty()) {
    int[] current = queue.poll();
    int currentSquare = current[0];
    int currentMove = current[1];
    
    if (currentSquare == 100) {
      return currentMove;
    }

    for (int i = currentSquare + 1; i <= currentSquare + 6; i++) {
      if (i <= 100 && !visited[board[i]]) {
        visited[i] = true;
        visited[board[i]] = true;
        queue.offer(new int[] {board[i], currentMove + 1});
        
      }
    }
  }
  return -1;
}

def quickestWayUp(ladders, snakes):
    n_moves = [-1]*101
    n_moves[1] = 0
    todo = [1]
    ladders_dict = {min(i,j): max(i,j) for i, j in ladders}
    snakes_dict = {max(i,j): min(i,j) for i, j in snakes}
    while todo:
        start = todo.pop()
        for x in range(start + 1, start + 7):
            x = ladders_dict.get(x, snakes_dict.get(x, x))
            if x > 100:
                break
            if (n_moves[x] == -1) or (n_moves[x] > n_moves[start] + 1):
                n_moves[x] = n_moves[start] + 1
                todo.append(x)
    return n_moves[100]