[Leetcode] [Java] Path Sum II

Title:

Given a binary tree and a sum, find all root-to-leaf paths where each path ' s sum equals the Given sum.

For Example:
Given The below binary tree sum = 22 and ,

              5             /             4   8           /   /           /  4         /  \    /         7 2 5   1

Return

[   [5,4,11,2],   [5,8,4,5]]

Test Instructions:

Given a binary tree and a sum, find all the paths of the node values from the root node to the leaf node in the Traverse and equal to the given target value.

Like what:

Given the following two-fork tree and sum = 22 ,

              5             /             4   8           /   /           /  4         /  \    /         7 2 5   1

Return

[   [5,4,11,2],   [5,8,4,5]]

Algorithm Analysis:

* Similar to the title "Path Sum"

* Also using recursive strategies

* The difference is that the subject needs to log the path of the search while traversing Dfs

 *  But it's important to Note that the cleanup works when recursion comes back up.

AC Code:

/** * Definition for Binary tree * public class TreeNode {* int val, * TreeNode left, * TreeNode right; TreeNode (int x) {val = x;} *} */public class Solution {public arraylist<arraylist<integer>> pathsum (Tr Eenode root, int sum) {arraylist<arraylist<integer>> res=new arraylist<arraylist<integer>>        ();        Helper (Root,sum,new arraylist<integer> (), res);    return res; } public void Helper (TreeNode root,int sum,arraylist<integer> cur,arraylist<arraylist<integer>> Res        ) {if (root==null) return; Reach the leaf node and the root node value equals sum if (root.left==null && root.right==null && root.val==sum) {CU            R.add (Root.val);            Res.add (New arraylist<integer> (cur));            Clear Operation Cur.remove (Cur.size ()-1);        Return      }//does not reach the leaf node, the left subtree is not empty if (root.left!=null) {cur.add (root.val);      Recursive call Helper (root.left,sum-root.val,cur,res) for Zuozi;        On return, clear Operation Cur.remove (Cur.size ()-1);            }//does not reach the leaf node, the right subtree is not empty if (root.right!=null) {cur.add (root.val);            Recursive call Helper (root.right,sum-root.val,cur,res) for right subtree;        On return, clear Operation Cur.remove (Cur.size ()-1); }                }}

Copyright NOTICE: This article is the original article of Bo Master, reprint annotated source

[Leetcode] [Java] Path Sum II