数据结构-单向链表

单向链表实现

链表让我们删除数据和新增数据更加方便！

head指针指向第一个存入的元素节点，每个节点都有next属性指向一下一个元素节点，最后一个元素的指针指向null

// 节点
class Node {
  constructor(element) {
    this.next = null;
    this.element = element;
  }
}
// 链表
class LinkList {
  constructor() {
    this.length = 0;
    this.head = null;
  }
  //   新增一个节点
  append(element) {
    // 新建一个node
    const node = new Node(element);
    if (this.length === 0) {
      this.head = node;
    } else {
      let current = this.head;
      while (current.next) {
        current = current.next;
      }
      current.next = node;
    }
    this.length++;
  }
  inster(position, element) {
    if (position >= 0 && position < this.length) {
      const node = new Node(element);
      if (position === 0) {
        node.next = this.head;
        this.head = node;
      } else {
        let current = this.head;
        let index = 0;
        let per = null;
        while (index++ < position) {
          per = current;
          current = current.next;
        }
        node.next = current;
        per.next = node;
      }
      this.length++;
    }
  }
  removeAt(position) {
    if (position >= 0 && position < this.length) {
      if (position === 0) {
        this.head = this.head.next;
      } else {
        let current = this.head;
        let index = 0;
        let per = null;
        while (index++ < position) {
          per = current;
          current = current.next;
        }
        per.next = current.next;
      }
      this.length--;
    }
  }
  update(postion, element) {
    if (postion >= 0 && postion < this.length) {
      if (postion === 0) {
        this.head.element = element;
      } else {
        let current = this.head;
        let index = 0;
        while (index++ < position) {
          current = current.next;
        }
        current.element = element;
      }
    }
  }
}


// 调用
const linkList = new LinkList();
// 新增节点
linkList.append("1");
linkList.append("2");
linkList.append("3");
console.log(linkList);
//  {
//   length: 3,
//   head: {
//     next: {
//       next: {
//         next: null,
//         element: "3",
//       },
//       element: "2",
//     },
//     element: "1",
//   },
// }
// 插入
linkList.inster(1, "4");
console.log(linkList);
//  {
//   length: 4,
//   head: {
//     next: {
//       next: {
//         next: {
//           next: null,
//           element: "3",
//         },
//         element: "2",
//       },
//       element: "4",
//     },
//     element: "1",
//   },
// }
// 删除位置1
linkList.removeAt(1);
//  {
//   length: 3,
//   head: {
//     next: {
//       next: {
//         next: null,
//         element: "3",
//       },
//       element: "2",
//     },
//     element: "1",
//   },
// }

// 更新数据
linkList.update(0, "5");
//  {
//   length: 3,
//   head: {
//     next: {
//       next: {
//         next: null,
//         element: "3",
//       },
//       element: "2",
//     },
//     element: "5",
//   },
// }