[leetcode] 104. Maximum Depth of Binary Tree

링크

/**
 * 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 {
    static int max;
    public int maxDepth(TreeNode root) {
        max = 0;
        check(root, 0);
        return max;
    }

    public void check(TreeNode node, int cnt) {
        if (node == null) {
            if (cnt > max) {
                max = cnt;
            }
            return;
        }
        check(node.left, cnt + 1);
        check(node.right, cnt + 1);
    }

    
}

 

릿코드에서 static을 쓸때는 꼭 시작점에서 한번씩 초기화해줘야함.