1302. 层数最深叶子节点的和

比眉伴天荒 2022-12-20 11:09 74阅读 0赞

# 题目来源 #

[1302. 层数最深叶子节点的和][1302.]

# 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 maxDepth = 0;
        private int ans;
        public int deepestLeavesSum(TreeNode root) {
        
            if (root == null){
        
                return 0;
            }
    
            helper(root, 0);
    
            return ans;
        }
    
        private void helper(TreeNode root, int depth){
        
            if (root.left == null && root.right == null){
        
                if (depth > maxDepth){
        
                    maxDepth = depth;
                    ans  = root.val;
                }else if (depth == maxDepth){
        
                    ans  += root.val;
                }
    
                return;
            }
    
            if (root.left != null){
        
                helper(root.left, depth + 1);
            }
    
            if (root.right != null){
        
                helper(root.right, depth + 1);
            }
        }
    }

![在这里插入图片描述][20201111195555902.png_pic_center]

[1302.]: https://leetcode-cn.com/problems/deepest-leaves-sum/
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poaXpoZW5nZ3Vhbg_size_16_color_FFFFFF_t_70_pic_center]: /images/20221120/77faba0158c748feb68fc5b954b2eab9.png
[20201111195555902.png_pic_center]: /images/20221120/d501ce354d624f1d9c725d046cf597fd.png