https://github.com/emahtab/path-sum

https://github.com/emahtab/path-sum

dfs leetcode tree

Last synced: about 1 month ago
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• Host: GitHub
• URL: https://github.com/emahtab/path-sum
• Owner: eMahtab
• Created: 2021-08-21T00:59:11.000Z (about 4 years ago)
• Default Branch: main
• Last Pushed: 2021-08-21T01:04:06.000Z (about 4 years ago)
• Last Synced: 2025-03-28T01:30:10.768Z (8 months ago)
• Topics: dfs, leetcode, tree
• Homepage:
• Size: 21.5 KB
• Stars: 1
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

          
# Path Sum 

## https://leetcode.com/problems/path-sum

Given the root of a binary tree and an integer targetSum, return true if the tree has a root-to-leaf path such that adding up all the values along the path equals targetSum.

A leaf is a node with no children.

![Path Sum example](pathsum.jpg?raw=true "Root to Leaf Path Sum")

# Implementation : DFS

```java

/**

 * Definition for a binary tree node.

 * public class TreeNode {

 *     int val;

 *     TreeNode left;

 *     TreeNode right;

 *     TreeNode() {}

 *     TreeNode(int val) { this.val = val; }

 *     TreeNode(int val, TreeNode left, TreeNode right) {

 *         this.val = val;

 *         this.left = left;

 *         this.right = right;

 *     }

 * }

 */

class Solution {

    public boolean hasPathSum(TreeNode root, int targetSum) {

        if(root == null)

            return false;

        return traverse(root, targetSum);

    }

    

    private boolean traverse(TreeNode node, int targetSum) {

        if(node.left == null && node.right == null && node.val == targetSum)

            return true;

        boolean leftPath = false;

        if(node.left != null)

            leftPath = traverse(node.left, targetSum - node.val);

        boolean rightPath = false;

        if(node.right != null)

            rightPath = traverse(node.right, targetSum - node.val);

        

        return leftPath || rightPath;

    }

}

```