题解 | #二叉树中是否存在节点和为指定值的路径#

import java.util.*;

/*
 * public class TreeNode {
 *   int val = 0;
 *   TreeNode left = null;
 *   TreeNode right = null;
 * }
 */

public class Solution {
    /**
     * 
     * @param root TreeNode类 
     * @param sum int整型 
     * @return bool布尔型
     */
    public boolean hasPathSum (TreeNode root, int sum) {
        // write code here
        boolean left=false,right=false;
        if(root==null) return false;
        if(root.val == sum && root.left==null && root.right==null) return true;
        if(root.left!=null) left = hasPathSum(root.left,sum-root.val);
        if(root.right!=null) right = hasPathSum(root.right,sum-root.val);
        return left || right;
    }
}