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🟡 剑指 Offer II 049. 从根节点到叶节点的路径数字之和

LeetCode 提示

题目难度 中等

原题链接 🔗 leetcode

题解1#

就遍历

/** * 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 {    private int res = 0;
    private void dfs(int parent, TreeNode node) {        if (node == null) {            return;        }
        int nxtPrt = parent * 10 + node.val;
        if (node.left == null && node.right == null) {            res += nxtPrt;            return;        }
        if (node.left != null) {            dfs(nxtPrt, node.left);        }
        if (node.right != null) {            dfs(nxtPrt, node.right);        }    }
    public int sumNumbers(TreeNode root) {        dfs(0, root);
        return res;    }}