Binary Tree Paths

李增田发布于2019-08-14 16:50 / 2078人阅读

摘要：解题思路求根节点到叶子节点的路径集合，采用深度搜索，利用递归实现。

Binary Tree Paths
Given a binary tree, return all root-to-leaf paths.

For example, given the following binary tree:

</>复制代码 
   1
 /   
2     3
 
  5

All root-to-leaf paths are:

</>复制代码 
["1->2->5", "1->3"]

1.解题思路

求根节点到叶子节点的路径集合，采用深度搜索，利用递归实现。

2.代码

</>复制代码 
public class Solution {
    List res=new ArrayList();
    public List binaryTreePaths(TreeNode root) {
        helper(root,new String());
        return res;
        
    }
    private void helper(TreeNode root,String pre){
        if(root==null)  return;
        if(root.left==null&&root.right==null){
            res.add(pre+root.val);
            return;
        }
        helper(root.left,pre+root.val+"->");
        helper(root.right,pre+root.val+"->");
    }
}

GPU云服务器云服务器 binary-tree binary-search-tree Paths Binary

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