0112 - Path Sum

0112 - 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.

Examples

Input: root = [5,4,8,11,null,13,4,7,2,null,null,null,1], targetSum = 22 Output: true Input: root = [1,2,3], targetSum = 5 Output: false

Input: root = [1,2], targetSum = 0 Output: false

Constraints

The number of nodes in the tree is in the range [0, 5000]. -1000 <= Node.val <= 1000 -1000 <= targetSum <= 1000

Java Solution

/**
 * 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;
        targetSum -= root.val;
        
        if(root.left == null && root.right == null) {
            return targetSum == 0;
        }

        return hasPathSum(root.left, targetSum) || hasPathSum(root.right, targetSum);
    }
}