Ejemplo n.º 1
0
 public int totalNQueens(int n) {
   StringBuilder[] board = new StringBuilder[n];
   for (int i = 0; i < n; i++) {
     board[i] = new StringBuilder();
     for (int j = 0; j < n; j++) {
       board[i].append('.');
     }
   }
   for (int i = 0; i < n / 2; i++) {
     board[0].setCharAt(i, 'Q');
     dfs(n, 1, board);
     board[0].setCharAt(i, '.');
   }
   ArrayList<String[]> aux = new ArrayList<String[]>();
   for (String[] k : res) {
     String[] tmp = new String[n];
     for (int i = 0; i < n; i++) {
       StringBuilder sb = new StringBuilder(k[i]).reverse();
       tmp[i] = sb.toString();
     }
     aux.add(tmp);
   }
   res.addAll(aux);
   if (n % 2 != 0) {
     board[0].setCharAt(n / 2, 'Q');
     dfs(n, 1, board);
     board[0].setCharAt(n / 2, '.');
   }
   return res.size();
 }
Ejemplo n.º 2
0
 public static ArrayList<String> serializeTree(TreeNode tree) {
   ArrayList<String> res = new ArrayList<>();
   LinkedList<TreeNode> queue = new LinkedList<>();
   queue.addLast(tree);
   while (!queue.isEmpty()) {
     TreeNode node = queue.removeFirst();
     if (node == null) {
       res.add(NULL);
     } else {
       res.add(String.valueOf(node.val));
       queue.add(node.left);
       queue.add(node.right);
     }
   }
   while (res.size() > 1 && res.get(res.size() - 1).equals(NULL)) {
     res.remove(res.size() - 1);
   }
   return res;
 }