[C#][LeetCode][Easy] 104. Maximum Depth of Binary Tree

心得:

這題是典型的遞迴題目,題目要求找到二元樹最深的層級為多少。

這題的解法很簡單,先宣告兩個變數分別來儲存左邊與右邊的層級,首先判斷左邊是否為空,若非為空值則會繼續搜尋此節點的子節點是否為空,搜尋完畢後再一併回傳至第一層的left變數裡,右邊反之,最後在比較左右兩邊哪個最大,最大的數字即為二元樹的層級。

問題:

Given a binary tree, find its maximum depth.

The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

答案:

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     public int val;
 *     public TreeNode left;
 *     public TreeNode right;
 *     public TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    public int MaxDepth(TreeNode root) {
        if (root == null)
        {
            return 0;
        }

        int left = 1;
        int right = 1;

        if (root.left != null)
        {
            left += MaxDepth(root.left);
        }

        if (root.right != null)
        {
            right += MaxDepth(root.right);
        }

        return right > left ? right : left;
    }
}

參考:

  1. https://skyyen999.gitbooks.io/-leetcode-with-javascript/content/questions/104md.html


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