單鏈表的實現

這節我們實現一個單鏈表，有詳細的註釋。之前貼出代碼好了

/*
	鏈表數據結構的實現
*/

function LinkedList() {
	var Node = function (element) {
		this.element = element;
		this.next = null;
	}

	var length = 0;    
	var head = null;

	/*向列表尾部追加節點*/
	this.append = function (element) {
		var new_node = new Node(element);
		if(head == null) {
			head = new_node;
		} else {
			//insertNode(head, new_node);   // 使用遞歸來解決也可以
			var current = head;
			while(current.next != null) {
				current = current.next;
			}
			current.next = new_node;
		}

		length++;
	}

	// /*這裏*/
	// function insertNode(root, new_node) {
	// 	if(root.next == null) {
	// 		root.next = new_node;
	// 	} else {
	// 		insertNode(root.next, new_node);
	// 	}
	// }

	/*向列表特定位置插入節點*/
	this.insert = function (position, element) {
		if(position < 0 || position>this.size()-1) {
			throw new Error("Position should be in [0, " + (this.size() -1) + "]");
		}

		var new_node = new Node(element);
		if(position == 0) {
			new_node.next = head;
			head = new_node;
		} else {
			var current = head;
			for(var i=1; i<position; ++i) {
				current = current.next;
			}

			new_node.next = current.next;
			current.next = new_node;
		}
		length++;
	}

	/*移除特定位置的節點*/
	this.removeAt = function (position) {
		if(position < 0 || position>this.size()-1) {
			throw new Error("Position should be in [0, " + (this.size() -1) + "]");
		}

		if(position == 0) {
			head = head.next;
		} else {
			var current = head;
			for(var i=1; i<position; ++i) {
				current = current.next;
			}

			current.next = current.next.next;
		}

		length--;
	}

	/*按值相等移除遇到的第一個節點*/
	this.remove = function (element) {
		var index = this.indexOf(element);
		if(index == -1) {
			return;
		}

		this.removeAt(index);
	}

	/*按值相等返回遇到的第一個節點的位置*/
	this.indexOf = function (element) {
		var current = head;
		var cnt = -1;
		while(current != null) {
			cnt++;
			if(element == current.element) {
				return cnt;
			}
			current = current.next;
		}

		if(current == null) {
			return -1;
		}
	}

	/*判斷鏈表是否爲空*/
	this.isEmpty = function () {
		return length == 0;
	}

	/*返回鏈表的大小*/
	this.size = function () {
		return length;
	}

	/*返回鏈表的頭指針或者稱爲引用*/
	this.getHead = function () {
		return head;
	}

	/*鏈表只輸出值*/
	this.toString = function () {
		var current = head;
		var arr = [];
		while(current != null) {
			arr.push(current.element);
			current = current.next;
		}

		return arr.join(",");
	}

	/*按順序打印鏈表*/
	this.print = function () {
		console.log(this.toString());
	}
}

/* Here is a test function */
function test(arr) {
	var linked_list = new LinkedList();
	for(var i=0; i<arr.length; ++i) {
		linked_list.append(arr[i])
	}

	return linked_list;
}

var arr = [10, 20, 30, 40, 50];
var result = test(arr);