1 public class Tree { 2     public Tree left; 3     public Tree right; 4     public int val; 5  6     public Tree() { 7  8     } 9 10     public Tree(String n) {11         this.val = Integer.parseInt(n);12     }13 14     public Tree createTreeByLevel(String[] var) {15         if (var == null) {16             return null;17         }18         if (var[0] == "#") {19             return null;20         }21         int length = var.length;22         Tree root = new Tree(var[0]);23         Tree cur = root;24         int count = 1;25         insertByLevelOrder(cur, length, count, var);26 27         return root;28     }29 30     void insertByLevelOrder(Tree cur, int length, int count, String[] var) {31         if (count * 2 - 1 >= length) {32             return;33         }34         if (var[count * 2 - 1] != "#") {35             cur.left = new Tree(var[count * 2 - 1]);36         } else37             cur.left = null;38         if (count * 2 >= length) {39             return;40         }41         if (var[count * 2] != "#") {42             cur.right = new Tree(var[count * 2]);43         } else44             cur.right = null;45         if (cur.left != null)46             insertByLevelOrder(cur.left, length, count * 2, var);47         if (cur.right != null)48             insertByLevelOrder(cur.right, length, count * 2 + 1, var);49         // return cur;50     }51 52     @Override53     public String toString() {54         String result = "";55         result = result + this.val + " ";56         Tree t = this;57         if (t.left != null) {58 59             result += t.left.toString();60         }61         if (t.right != null) {62             result += t.right.toString();63         }64         return result;65     }66 }