1315. 祖父节点值为偶数的节点和

快来打我* 2022-12-20 14:53 221阅读 0赞

# 题目来源 #

[1315. 祖父节点值为偶数的节点和][1315.]

# 题目描述 #

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poaXpoZW5nZ3Vhbg_size_16_color_FFFFFF_t_70_pic_center]

# 题目解析 #

/**
     * Definition for a binary tree node.
     * public class TreeNode {
     *     int val;
     *     TreeNode left;
     *     TreeNode right;
     *     TreeNode(int x) { val = x; }
     * }
     */
    class Solution {
        
        private int ans;
        public int sumEvenGrandparent(TreeNode root) {
        
            helper(root, null, null);
            return ans;
        }
    
        private void helper(TreeNode root, TreeNode grandfather, TreeNode father){
        
            if (root == null){
        
                return;
            }
            
            if (grandfather != null && grandfather.val %2 == 0){
        
                ans += root.val;
            }
            
           
            helper(root.left, father, root);
            helper(root.right, father, root);
        }
    }

![在这里插入图片描述][20201112210916795.png_pic_center]

[1315.]: https://leetcode-cn.com/problems/sum-of-nodes-with-even-valued-grandparent/
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poaXpoZW5nZ3Vhbg_size_16_color_FFFFFF_t_70_pic_center]: /images/20221120/848ed294de2a4ec48c5e2107475044f3.png
[20201112210916795.png_pic_center]: /images/20221120/3e9bc02beef448498f6fea94c3735adb.png