使用TypeScript实现单链表

1.节点类ListNode

class ListNode<K>{
    public next: ListNode<K> | null;
    constructor(public element: K) {
        this.next = null;
    }
}

2.链表类LinkList

class LinkList<T>{
    public count: number;
    public head: ListNode<T> | null;
    constructor() {
        this.head = null;
        this.count = 0;
    }
    /**
     * 在链表尾部插入元素
     * @param element 
     */

    push(element: T){
        const node = new ListNode(element);
        if (this.head == null) {
            this.head = node;
        } else {
            let current = this.head;
            while (current.next != null) {
                current = current.next
            }
            current.next = node;
        }
        this.count++;
    }
    /**
     * 通过位置索引查找元素
     * @param index 
     */

    findByIndex(index: number):ListNode<T> | null {
        if (index < this.count && index >= 0) {
            if (this.head != null) {
                   let current = this.head;
                   let tmp: number = 0;
                   while (current.next != null&& tmp < index) {
                       current = current.next;
                       tmp++;
                }
                return current;
            }
            
        }
        return null;
    }
    /**
     * 移除指定位置的元素
     * @param index 
     */

    removeByIndex(index: number) {
        if (this.head != null) {
            if (index === 0) {
                this.head = this.head.next;
            } else {
                let previous = this.findByIndex(index - 1);
                let current = this.findByIndex(index)
                if (previous&&current) {
                    previous.next = current.next;
                    
                }
            }
            this.count--;
        }
    }
    /**
     * 查找元素位置，如果没有找到就返回-1
     * @param element 
     */

    findElIndex(element: T): number{
        let current = this.head;
        if (current == null) {
            return -1;
        } else {
            let index: number = 0;
            while (current.next != null) {
                if (current.element === element) {
                    return index;  
                }
                current = current.next;
                index++;
            }
            return -1;
        }
    }
    /**
     * 在指定位置插入元素
     * @param element 
     * @param index 
     */

    insert(element: T, index: number) {
        let previous = this.findByIndex(index - 1);
        let current = this.findByIndex(index);
        let newNode = new ListNode(element);
        if (previous && current) {
            previous.next = newNode;
            previous.next.next = current;
        }
        if (previous && !current) {
            previous.next = newNode;
        }
        if (current && !previous) {
            this.head = newNode;
            this.head.next = current;
        }
        this.count++;

    }
    /**
     * 将链表转换为字符串;
     */
    toString() {
        let tmpString: string = '';
        let current = this.head;
        if (current == null) {
            return ''
        } else {
            while (current.next != null) {
                tmpString = `${current.element}${tmpString}`;
                current = current.next;
            }
            return tmpString;
        }
    }

    
}