Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/emahtab/path-sum-ii
https://github.com/emahtab/path-sum-ii
dfs leetcode tree
Last synced: 3 days ago
JSON representation
- Host: GitHub
- URL: https://github.com/emahtab/path-sum-ii
- Owner: eMahtab
- Created: 2021-08-21T02:03:58.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2025-01-15T09:03:56.000Z (20 days ago)
- Last Synced: 2025-01-15T11:00:30.220Z (20 days ago)
- Topics: dfs, leetcode, tree
- Homepage:
- Size: 26.4 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# Path Sum II
## https://leetcode.com/problems/path-sum-ii
Given the root of a binary tree and an integer targetSum, return all root-to-leaf paths where the sum of the node values in the path equals targetSum. Each path should be returned as a list of the node values, not node references.
A root-to-leaf path is a path starting from the root and ending at any leaf node. A leaf is a node with no children.
# Implementation 1 : 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 List> pathSum(TreeNode root, int targetSum) {
List> result = new ArrayList<>();
if(root == null)
return result;
List path = new ArrayList<>();
traverse(root, targetSum, result, path);
return result;
}
private void traverse(TreeNode node, int targetSum, List> result, List path) {
path.add(node.val);
if(node.left == null && node.right == null && node.val == targetSum) {
result.add(path);
return;
}
if(node.left != null) {
traverse(node.left, targetSum - node.val, result, new ArrayList(path));
}
if(node.right != null)
traverse(node.right, targetSum - node.val, result, new ArrayList(path));
}
}
```
## Implementation 2 : DFS with Backtracking
```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 List> pathSum(TreeNode root, int targetSum) {
List> result = new ArrayList<>();
if(root == null)
return result;
traversePath(root, targetSum, 0, result, new ArrayList());
return result;
}
private void traversePath(TreeNode node, int targetSum, int runningSum, List> result, List path) {
runningSum += node.val;
path.add(node.val);
if(runningSum == targetSum && node.left == null && node.right == null) {
result.add(new ArrayList(path));
}
if(node.left != null)
traversePath(node.left, targetSum, runningSum, result, path);
if(node.right != null)
traversePath(node.right, targetSum, runningSum, result, path);
path.remove(path.size()-1);
}
}
```