1 package com.rust.datastruct; 2  3 import java.util.ArrayList; 4 import java.util.List; 5  6 /** 7  * judging 8  * Binary Tree Paths 9  *10  * Given a binary tree, return all root-to-leaf paths.11  *12  * For example, given the following binary tree:13  *14  *   115  * /   \16  * 2    317  * \18  * 519  * All root-to-leaf paths are:20  * ["1->2->5", "1->3"]21  */22 class BinaryTreePathsSolution {23     List
     
       res = new ArrayList
      
       ();24     public List
       
         binaryTreePaths(TreeNode root) {25         if (root != null) track(root, root.val + "");/* String.valueOf(root.val)*/26         return res;27     }28     private void track(TreeNode n, String path){29         if (n.left == null && n.right == null) res.add(path);30         if (n.left != null) track(n.left, path + "->" + n.left.val);/* continue tracking */31         if (n.right != null) track(n.right, path + "->" + n.right.val);32     }33 }34 35 /**36  * Test main37  */38 public class BinaryTreePaths {39     public static void main(String args[]) {40         TreeNode root = new TreeNode(0);41         TreeNode node1 = new TreeNode(1);42         TreeNode node2 = new TreeNode(2);43         TreeNode node3 = new TreeNode(3);44         TreeNode node4 = new TreeNode(4);45         TreeNode node5 = new TreeNode(5);46         TreeNode node6 = new TreeNode(6);47         TreeNode node7 = new TreeNode(7);48 49         root.left = node1;50         root.right = node2;51         node1.left = node3;52         node1.right = node4;53         node2.left = node5;54         node2.right = node6;55         node4.right = node7;56 57         BinaryTreePathsSolution solution = new BinaryTreePathsSolution();58         List
        
          res = solution.binaryTreePaths(root);59 60         for (int i = 0;i < res.size();i++){61             System.out.print(res.get(i) + " ");62         }63         System.exit(0);64     }65 66 }