JSFiddle - React, Tailwind, and code Playground

by Slava Slava

JavaScript

class Node {
  constructor(value) {
    this.value = value;
    this.next = null;
  }
}

class LinkedList {
  constructor(value) {
    const newNode = new Node(value);
    this.head = newNode;
    this.tail = newNode;
    this.length = 1;
  }

  printList() {
    let temp = this.head;
    while (temp !== null) {
      console.log(temp.value);
      temp = temp.next;
    }
  }

  getHead() {
    if (this.head === null) {
      console.log("Head: null");
    } else {
      console.log("Head: " + this.head.value);
    }
  }

  getTail() {
    if (this.tail === null) {
      console.log("Tail: null");
    } else {
      console.log("Tail: " + this.tail.value);
    }
  }

  getLength() {
    console.log("Length: " + this.length);
  }

  makeEmpty() {
    this.head = null;
    this.tail = null;
    this.length = 0;
  }

  push(value) {
    const newNode = new Node(value);
    if (!this.head) {
      this.head = newNode;
      this.tail = newNode;
    } else {
      this.tail.next = newNode;
      this.tail = newNode;
    }
    this.length++;
  }

  hasLoop() {
    try {
      let slow = this.head;
      let fast = this.head.next;

      while (slow) {
        if (slow === fast) {
          return true;
        }

        slow = slow.next;
        fast = fast.next.next;


      }
    } catch (e) {
      /* console.log('err end ', e) */
    }


    return false;
  }

}



let myLinkedList = new LinkedList(1);
myLinkedList.push(2);
myLinkedList.push(3);
myLinkedList.push(4);
myLinkedList.push(5);

console.log("Original list:");
myLinkedList.printList();

const hasLoopResult = myLinkedList.hasLoop();
console.log(`\nHas loop? ${hasLoopResult}`);

// Create a loop for testing purposes
myLinkedList.tail.next = myLinkedList.head.next; // Create a loop by linking tail to the second node

const hasLoopResultAfterLoop = myLinkedList.hasLoop();
console.log(`\nHas loop after creating a loop? ${hasLoopResultAfterLoop}`);


/*
    EXPECTED OUTPUT:
    ----------------
    Original...