LeetCode-C#实现-二叉树(#104/111)

/**
 * 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) {
        //若无根节点返回深度为0
        if(root==null) return 0;
        //声明集合保存各个叶节点的深度
        List<int> depthList = new List<int>();
        //搜索树的深度，传入根节点、集合、根节点深度
        Search(root,depthList,1);
        //获取集合中最大深度
        int maxDepth = int.MinValue;
        foreach(int depth in depthList)
            if (depth > maxDepth) maxDepth = depth;
        return maxDepth; 
    }
    public void Search(TreeNode root, List<int> depthList, int rootDepth){
        //如果节点左右子节点都不存在则为叶节点，将其深度存入集合
        if (root.left == null&& root.right == null)
            depthList.Add(rootDepth);
        //否则，继续递归遍历节点的左右节点，将节点的深度传给其左右子节点
        if (root.left != null)
            Search(root.left, depthList, rootDepth + 1);
        if (root.right != null)
            Search(root.right, depthList, rootDepth + 1);
    }
}