java如何用递归返回树结构的结果？
问题阐述：
需要实现一种算法，以树结构的形式返回给定名字的亲属关系链路。例如，以“秦朗”为搜索目标，结果应该返回“三国-曹操-秦朗”。
示例代码：
// 省略person类定义
public static void main(string[] args) {
// 构建人物关系树
person sunce = new person("孙策");
person sunquan = new person("孙权");
person sunjian = new person("孙坚");
sunjian.setchildren(arrays.aslist(sunce, sunquan));
person caopi = new person("曹丕");
person caozhi = new person("曹植");
person caozhang = new person("曹彰");
person qinlang = new person("秦朗");
person caocao = new person("曹操");
caocao.setchildren(arrays.aslist(caopi, caozhi, caozhang, qinlang));
person liufeng = new person("刘封");
person liushan = new person("刘禅");
person liubei = new person("刘备");
liubei.setchildren(arrays.aslist(liufeng, liushan));
person liuxun = new person("刘循");
person liuzhang = new person("刘璋");
liuzhang.setchildren(arrays.aslist(liuxun));
person liuyan = new person("刘焉");
liuyan.setchildren(arrays.aslist(liuzhang));
person sanguo = new person("三国");
sanguo.setchildren(arrays.aslist(sunjian, caocao, liubei, liuyan));
// 使用递归算法查询并打印结果
list<person> p1 = query(sanguo, "刘");
system.out.println(p1);
list<person> p2 = query(sanguo, "秦");
system.out.println(p2);
list<person> p3 = query(sanguo, "孙策");
system.out.println(p3);
}
// 递归查询返回亲属关系链路
public static list<person> query(person person, string name) {
list<person> result = new arraylist<>();
// 判空
if(person.getname().contains(name)) {
return arrays.aslist(person);
} else {
if(person.getchildren() != null) {
for (person child : person.getchildren()) {
result.addall(query(child, name));
}
}
}
return result;
}改进要求：
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用户提出希望返回的树结构中包含命中和未命中结果，且去掉未命中结果的子节点。
修改后代码：
// 省略person类定义
public static void main(string[] args) {
// 构建人物关系树
// ... 同上 ...
// 使用递归算法生成树形结果并打印
personvo sanguo = createtree(sanguo, -1);
list<personvo> resulttree = query(sanguo, "秦朗");
system.out.println(json.tojsonstring(resulttree));
}
// 生成树形结构
private static personvo createtree(person person, int parentid) {
personvo personvo = new personvo(person.getid(), parentid, person.getname());
if (person.getchildren() != null) {
for (person child : person.getchildren()) {
personvo.getchildren().add(createtree(child, person.getid()));
}
}
return personvo;
}
// 递归查询返回亲属关系链路
private static list<personvo> query(personvo person, string name) {
list<personvo> result = new arraylist<>();
if (person.getname().equals(name)) {
result.add(person);
return result;
} else {
for (personvo child : person.getchildren()) {
result.addall(query(child, name));
}
}
return result;
}改进后效果：
qinlang 的搜索结果：
[{
"id": 14
"parentid": 4,
"peoplename": "秦朗",
"children": [
{
"id": 4,
"parentid": 0,
"peoplename": "曹操",
"children": [
{
"id": 0,
"parentid": -1,
"peoplename": "三国"
}
]
}
]
}]sunjian 的搜索结果：
[{
"id": 3,
"parentId": 0,
"peopleName": "孙坚",
"children": [
{
"id": 0,
"parentId": -1,
"peopleName": "三国"
}
]
}]以上结果满足了用户提出的要求，返回的树形结构中包含所有命中和未命中的节点，且未命中的节点的子节点已被剔除。
