Java binary tree path and code examples

Given a binary tree, find the path where the sum of each node in all paths is equal to the given target value.

A valid path refers to the path from the root node to the leaf node.

Sample

Given a binary tree, and the target value = 5:

 1 / / 2 4 / / 2 3

return:

 [ [1, 2, 2], [1, 4]]

The code is as follows:

 /** * Definition of TreeNode: * public class TreeNode { * public int val; * public TreeNode left, right; * public TreeNode(int val) { * this.val = val; * this.left = this.right = null; * } * } */public class Solution {/** * @param root the root of binary tree * @param target an integer * @return all valid paths */public List<List<Integer>> binaryTreePathSum(TreeNode root, int target) {// Write your code herereturn dfs(root,new ArrayList<Integer>(),0,new ArrayList<List<Integer>(),target);}public List<List<Integer>> dfs(TreeNode root,List<Integer> node, int sum, List<List<Integer>> paths,int target) {if(root==null) {return new ArrayList<List<Integer>>();}List<List<Integer>> path=new ArrayList<List<Integer>>();if(root.left!=null) {List<Integer> nodes=new ArrayList<Integer>();if(node!=null) {nodes.addAll(node);}nodes.add(root.val);List<List<Integer>> temp=dfs(root.left,nodes,sum+root.val,paths,target);if(temp!=null) {path.addAll(temp);}}if(root.right!=null) {List<Integer> nodes=new ArrayList<Integer>();if(node!=null) {nodes.addAll(node);}nodes.add(root.val);List<List<Integer>> temp=dfs(root.right,nodes,sum+root.val,paths,target);if(temp!=null) {path.addAll(temp);}}if(root.left==null&&root.right==null) {List<Integer> nodes=new ArrayList<Integer>();if(node!=null) {nodes.addAll(node);}nodes.add(root.val);if(sum+root.val==target) {path.add(nodes);} else{path=new ArrayList<List<Integer>>();}} return path;}}

reference

Code analysis of the problem of finding the maximum path of binary tree in java programming

Inheritance test code analysis in java

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