Question

java 用递归创建二叉树，非递归遍历二叉树输出节点

求 解答 最近开始学的java。。

Answer 1

我自己用递归写了下，不知道能不能给你帮助：

测试类：
package tree;

import java.util.*;

public class Test {

public static void main(String[] args){
List<Tree> trees=new ArrayList<Tree>();
int id=1;
Tree tree1=new Tree(0,id++,"张三丰");
Tree tree2=new Tree(tree1.getId(),id++,"武当宋大侠宋远桥");
Tree tree3=new Tree(tree1.getId(),id++,"武当俞二侠俞莲舟");
Tree tree4=new Tree(tree1.getId(),id++,"武当俞三侠俞岱岩");
Tree tree5=new Tree(tree1.getId(),id++,"武当张四侠张松溪");
Tree tree6=new Tree(tree1.getId(),id++,"武当张五侠张翠山");
Tree tree7=new Tree(tree1.getId(),id++,"武当殷六侠殷梨亭");
Tree tree8=new Tree(tree1.getId(),id++,"武当莫七侠莫声谷");
Tree tree9=new Tree(tree6.getId(),id++,"明教张无忌");
Tree tree13=new Tree(tree2.getId(),id++,"叛徒宋青书");

Tree tree10=new Tree(0,id++,"任我行");
Tree tree11=new Tree(tree10.getId(),id++,"令狐冲");
Tree tree12=new Tree(tree10.getId(),id++,"任盈盈");

trees.add(tree1);
trees.add(tree2);
trees.add(tree3);
trees.add(tree4);
trees.add(tree5);
trees.add(tree6);
trees.add(tree7);
trees.add(tree8);
trees.add(tree9);
trees.add(tree10);
trees.add(tree11);
trees.add(tree12);
trees.add(tree13);

for(int i=0;i<trees.size();i++){
Tree tree=trees.get(i);
if(tree.getParentId()==0){
tree.showChildTree(trees);
}
}

}

}

树类：
package tree;

import java.util.List;

public class Tree {
private int parentId;
private int id;
private String showStr;
private String Spaces="";

public Tree() {
// TODO Auto-generated constructor stub
}
public Tree(int parentId,int id,String showStr){
this.parentId=parentId;
this.id=id;
this.showStr=showStr;
}

public void showChildTree(List<Tree> trees){
if(parentId!=0){
trees.get(id-1).setSpaces(trees.get(parentId-1).getSpaces()+" ");
}
System.out.println(trees.get(id-1).getSpaces()+showStr);
for(int i=0;i<trees.size();i++){
Tree tree=trees.get(i);
if(tree.getParentId()==id){
tree.showChildTree(trees);
}
}

}

public int getParentId() {
return parentId;
}

public void setParentId(int parentId) {
this.parentId = parentId;
}

public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

public String getShowStr() {
return showStr;
}

public void setShowStr(String showStr) {
this.showStr = showStr;
}

public String getSpaces() {
return Spaces;
}

public void setSpaces(String spaces) {
Spaces = spaces;
}

}

效果图：
张三丰
武当宋大侠宋远桥
叛徒宋青书
武当俞二侠俞莲舟
武当俞三侠俞岱岩
武当张四侠张松溪
武当张五侠张翠山
明教张无忌
武当殷六侠殷梨亭
武当莫七侠莫声谷
任我行
令狐冲
任盈盈