JavaScript:解决算法问题

Question

今天我在做一个问题，它的状态如下:

问题:

• 输入:[{..}, {..}, ..]对象数组；
• 每个对象都有 {"id": required, "children": []}
• 根据"id" and "children"，对象具有父子关系 Prop
• 输出:[{..}, {..}, ..]树状数组(层次结构)顺序:多级。

---

输入:

[{
    "id": 1,
    "name": "Earth",
    "children": [2, 3]
}, {
    "id": 2,
    "name": "Asia",
    "children": []
}, {
    "id": 3,
    "name": "Europe",
    "children": [4]
}, {
    "id": 4,
    "name": "Germany",
    "children": [5]
}, {
    "id": 5,
    "name": "Hamburg",
    "children": []
}]

---

输出

[{
    "id": 1,
    "name": "Earth",
    "children": [{
        "id": 2,
        "name": "Asia",
        "children": []
    }, {
        "id": 3,
        "name": "Europe",
        "children": [{
            "id": 4,
            "name": "Germany",
            "children": [{
                "id": 5,
                "name": "Hamburg",
                "children": []
            }]
        }]
    }]
}]

我的方法

我决定通过遍历数组中的每个元素并递归查找对象并将其附加到 children 来解决这个问题 每个元素。

So just to start with, I decided to have only First level children appended their respective parents. And my code is following.

var posts = [{"id":1,"name":"Earth","children":[2,3]},{"id":2,"name":"Asia","children":[]},{"id":3,"name":"Europe","children":[4]},{"id":4,"name":"Germany","children":[5]},{"id":5,"name":"Hamburg","children":[]}]

function getElementById (id, posts) {
	for(var i =0; i< posts.length; i++){
		if(posts[i].id === id){
			var found = posts[i];
///// FUN here -> ////	posts.splice(i, 1);
			return found;
		}
	}
} 

function refactorChildren(element, posts) {
  if(!element.children || element.children.length === 0) {
    return element;
  }
  
  var children = [];
  for(var i = 0; i < element.children.length; i++){
    var childElement = getElementById(element.children[i], posts);    
    children.push(childElement);
  }
  element.children = children;
  
  return element;
}

function iterate(posts) {
  var newPosts = [];
  var des = [...posts]
  for(var i = 0; i < des.length; i++){
    var childedElement = refactorChildren(des[i], des);
     newPosts.push(childedElement);
  }
  
  return newPosts;
}


var filtered = iterate(posts);
console.log(JSON.stringify(filtered))

Surprisingly above code Solves the ACTUAL PROBLEM (except a lil bit of more work)

我的预期结果应如下所示: 只有第一级 child

的对象数组

[{
    "id": 1,
    "name": "Earth",
    "children": [{
        "id": 2,
        "name": "Asia",
        "children": []
    }, {
        "id": 3,
        "name": "Europe",
        "children": [4]
    }]
}, {
    "id": 4,
    "name": "Germany",
    "children": [{
        "id": 5,
        "name": "Hamburg",
        "children": []
    }]
}]

如果我取消对 ///// FUN here -> //// 的注释，我确实会得到上述结果线。这是在移动中删除迭代对象。

所以我的问题是

我想知道 - 怎么做到的？所有对象都通过该代码正确附加到它们各自的父对象吗？我的下一步是添加对函数 refactorChildren(with-childElement) 的递归调用。 .

和

怎么做到的，就是加了posts.splice(i, 1);从代码中得到了我的预期结果？

请帮助我理解，我只是不知道“怎么做”才能继续。

谢谢

Answer 1

在遍历对象时，您递归地对其所有子对象调用一个函数并从数组中删除对象:

 [
   { id: 1, children: [2], }, // < iterator
   { id: 2, children: [] }, // < gets spliced out recursively
 ]

但是，如果子项位于其父项之前的数组中，则这将不起作用，因为您在访问父项之前将子项复制到另一个数组中。