https://leetcode.com/problems/path-sum/
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22/**
* 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;
if(root.left==null&&root.right==null&&targetSum==root.val) return true;
return hasPathSum(root.left,targetSum-root.val)||hasPathSum(root.right,targetSum-root.val);
}
}