Recursion Solution for Path Sum

Problem: Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.

 

 


/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    public boolean hasPathSum(TreeNode root, int sum) {
        
        if(root == null) return false;
        
        if(root.val == sum && root.left == null && root.right == null){
            return true;
        }
        
        return hasPathSum(root.left, sum - root.val) || hasPathSum(root.right, sum - root.val);
        
    }
}
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