leetcode543. 二叉树的直径

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    int ans = 1;
    public int diameterOfBinaryTree(TreeNode root) {        
        depth(root);
        return ans - 1;
    }

    private int depth(TreeNode node) {
        if (node == null)
            return 0;
        int L = depth(node.left);
        int R = depth(node.right);
        ans = Math.max(ans, L + R + 1);
        return Math.max(L, R) + 1;
    }
}

来源：CSDN

作者：wl1929

链接：https://blog.csdn.net/wl1929/article/details/104478286