[Leetcode] Path Sum (Java)

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.

For example:
Given the below binary tree and sum = 22,

              5             / \            4   8           /   / \          11  13  4         /  \      \        7    2      1

return true, as there exist a root-to-leaf path 5->4->11->2 which sum is 22.

找是否有从根root到叶子节点leaf的和为给定值sum的路线

DFS

public class Solution {    public boolean hasPathSum(TreeNode root, int sum) {        if(root==null){return false;}if(sum==root.val&&root.left==null&&root.right==null)return true;if(root.left!=null)if(hasPathSum(root.left, sum-root.val))return true;if(root.right!=null){if(hasPathSum(root.right, sum-root.val))return true;}return false;    }}