leetcode589. N叉树的前序遍历（java）

问题描述：

给定一个 N 叉树，返回其节点值的前序遍历。

例如，给定一个 3叉树 :

返回其前序遍历: [1,3,5,6,2,4]。

上代码，拿去即可运行：

package com.onlyqi.upup01.tree;

import java.util.List;

public class TreeNode {
    private List TreeNodeList;
    private Integer value;

    public TreeNode() {
    }

    public TreeNode(List treeNodeList, Integer value) {
        TreeNodeList = treeNodeList;
        this.value = value;
    }
    public TreeNode( Integer value) {
        this.value = value;
    }


    public List getTreeNodeList() {
        return TreeNodeList;
    }

    public void setTreeNodeList(List treeNodeList) {
        TreeNodeList = treeNodeList;
    }

    public Integer getValue() {
        return value;
    }

    public void setValue(Integer value) {
        this.value = value;
    }
}

package com.onlyqi.upup01.tree;

import java.util.ArrayList;
import java.util.List;

public class Test04 {
    public static void main(String[] args) {
        TreeNode treeNode1 = new TreeNode(null, 1);
        TreeNode treeNode2 = new TreeNode(null, 2);
        TreeNode treeNode3 = new TreeNode(null, 3);
        TreeNode treeNode4 = new TreeNode(null, 4);
        TreeNode treeNode5 = new TreeNode(null, 5);
        TreeNode treeNode6 = new TreeNode(null, 6);
        List list1 = new ArrayList<>();
        list1.add(treeNode3);
        list1.add(treeNode2);
        list1.add(treeNode4);
        List list2 = new ArrayList<>();
        list2.add(treeNode5);
        list2.add(treeNode6);
        treeNode3.setTreeNodeList(list2);
        treeNode1.setTreeNodeList(list1);
        lastOrderTraversal(treeNode1);
    }

    static void lastOrderTraversal(TreeNode treeNode) {
        System.out.println("===========" + treeNode.getValue()); // 打印根

        if (treeNode != null) {
            if( treeNode.getTreeNodeList() != null){
                for (TreeNode node : treeNode.getTreeNodeList()) {
                    lastOrderTraversal(node);
                }
            }
        }
    }
}

运行结果：

我要刷100道算法题，第84道