我将如何在 JS 中创建树状数据结构,在那里,我可以访问诸如对父节点的引用、基于 id 的节点查找、访问子节点的长度(数量)、基于索引的内容查找等?
这基本上是我设想的 API:
var rootNode = DataStructure.getRoot();
var child1 = rootNode.addNode('child1'); //added a node with id 'child1'
child1.addNode('innerChild1');
child1.addNode('innerChild2');
rootNode.getChildById('child1') //should be same node as var child1
rootNode.getAtIndex(0) //should be same node as var child1
child1.parent() //should be rootNode
child1.getAtIndex(0) // should be node with id 'innerChild1'
child1.getAtIndex(1) // should be node with id 'innerChild2'
child1.length() //should be 2
等..
我理解这是一个广泛的问题,但我想知道是否有人可以推荐一种方法来解决这个问题和/或任何可能已经在做的图书馆?我应该动态创建一个 XML 并使用它的本地方法吗?那会是最快的吗?
最佳答案
您描述的数据结构可以很容易地实现如下:
var Tree = defclass({
constructor: function (parent) {
this.parent = parent || null; // null for root node
this.children = {}; // for id based lookup
this.ids = []; // for index based lookup
this.length = 0; // for ease of access
},
addNode: function (id) {
var children = this.children;
if (children.hasOwnProperty(id)) throw new Error(id + " exists");
return children[this.ids[this.length++] = id] = new Tree(this);
},
getChildById: function (id) {
var children = this.children;
if (children.hasOwnProperty(id)) return children[id];
throw new Error(id + " does not exist");
},
getAtIndex: function (index) {
return this.getChildById(this.ids[index]);
}
});
function defclass(prototype) {
var constructor = prototype.constructor;
constructor.prototype = prototype;
return constructor;
}
<script>
setTimeout(function () {
var rootNode = new Tree;
var child1 = rootNode.addNode("child1");
var innerChild1 = child1.addNode("innerChild1");
var innerChild2 = child1.addNode("innerChild2");
console.assert(rootNode.getChildById("child1") === child1);
console.assert(rootNode.getAtIndex(0) === child1);
console.assert(child1.parent === rootNode);
console.assert(child1.getAtIndex(0) === innerChild1);
console.assert(child1.getAtIndex(1) === innerChild2);
console.assert(child1.length === 2);
alert("success");
}, 0);
</script>
基于 id 的查找和基于索引的查找都采用常量(即 O(1)
)time .希望对您有所帮助。
关于javascript - JS中的树状数据结构允许最快的节点查找?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/29570744/