最近公共祖先（美團在線編程題）

package com.company;

import java.io.BufferedInputStream;
import java.util.Scanner;

/**
 * 美團在線編程題，最近公共祖先,使用後序遍歷做
 */
class Node {
    Node lchild;
    Node rchild;
    int val;

    Node(int val) {
        this.val = val;
    }
}

public class Main1 {

    public static Node getAncestor(Node head, Node s, Node t) {
        if (head == null || head == s || head == t) {
            return null;
        }
        Node left = getAncestor(head.lchild, s, t);
        Node right = getAncestor(head.rchild, s, t);

        if (left != null && right != null) {
            return head;
        }
        return left != null ? left : right;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(new BufferedInputStream(System.in));
        while (in.hasNext()) {

        }
    }
}