@geekyorion/DSAlib

A data structure library which implements linkedlist, tree, etc

DSA Status

• [x] LinkedList
  • [x] Singly LinkedList
  • [ ] Dobuly LinkedList
• [ ] Tree
• [ ] Stack
• [ ] Graph

basic usage

installation

To install the library please use the following command

npm i --save @geekyorion/dsa

creating instances

const LinkedList = require('@geekyorion/dsa').LinkedList;

// use the LinkedList to create a new list
const list = new LinkedList();

OR

const DSA = require('@geekyorion/dsa');
// here DSA is an object which has implemeneted Data structure within

// to create a new LinkedList
const list = new DSA.LinkedList();

1. LinkedList

Class Prototype

// properties
list.head: null | LinkedListNode
list.tail: null | LinkedListNode
list.lengthOfList: number

// method list
list.getHead(): LinkedListNode;
list.getTail(): LinkedListNode;
list.getLength(): number;
list.JSON(): JSON;
list.push(value: any): number;
list.unshift(value: any): number;
list.pop(): LinkedListNode.value;
list.shift(): LinkedListNode.value;
list.traverse(shouldReturnArray?: boolean): Array<LinkedListNode.value> | undefined;
list.insert(position: number, value: any): number;
list.remove(position: number): LinkedListNode.value;
list.removeByValue(value: LinkedListNode.value, multiRemove?: boolean): number;
list.reverse(): list;
list.getReversedValue(): Array<LinkedListNode.value>;
list.sort(shouldReturn?: boolean): list | true;
list.isEqual(anotherLinkedList: LinkedList): boolean;
list.merge(anotherLinkedList: LinkedList): number;
list.node(value: any): LinkedListNode;

Properties

const list = new LinkedList();

// get head pointer of the list
list.getHead();
// or
list.head;

// get tail pointer of the list
list.getTail();
// or
list.tail;

// get the number of nodes in the list
list.getLength();
// or
list.lengthOfList;

// All these properties can be used to generate the JSON for the list
// so to get the JSON for the list (with above properties)
list.JSON();
/*
example list: [1, 2, 3]
output:
{
    head: {
        value : 1, next: {
            value: 2, next: { value: 3, next: null }
        }
    },
    tail: {
        value: 3,
        next: null
    },
    lengthOfList: 3
}
*/

Available methods

• push(value): adds a new value in the list at the last position (after the tail)

  list.push(1);       // return value: 1
  list.push('a');     // return value: 2
  // returns the new size of the list
  // list: [1, 'a']

• unshift(value): adds a new value in the list at starting position (before the head)

  list.unshift(1);       // return value: 1
  list.unshift('a');     // return value: 2
  // returns the new size of the list
  // list: ['a', 1];

• pop(): removes the last value (from the tail)

  // list: [1, 2, 3, 4]
  const value = list.pop();
  // value: 4; returns the popped value
  // list: [1, 2, 3];

• shift(): removes the starting value (from the head)

  // list: [1, 2, 3, 4]
  const value = list.shift();
  // value: 1; returns the popped value
  // list: [2, 3, 4];

• traverse(shouldReturnArray?): traverse the linkedlist

  • shouldReturnArray: optional; default is true
    • true: returns the array of the list values
    • false: console the list items

  // list: [1, 2, 3, 4]
  const arrayItems = list.traverse();
  // arrayItems: [1, 2, 3, 4]; 
    
  list.traverse(false);
  // console output:
  /*
  1
  2
  3
  4
  */

• insert(position, value): insert a value at particular position (zero based index)

  // list: [1, 2, 4, 5]
  list.insert(2, 3);     // return value: 5
  // returns the new size of the list
  // list: [1, 2, 3, 4, 5];

• remove(position): remove a value from particular position (zero based index)

  // list: [1, 2, 3, 4, 5]
  const removedValue = list.remove(2);
  // removedValue: 3; returns the removed value
  // list: [1, 2, 4, 5];

• removeByValue(value, multiRemove?): removes the given value from list

  • multiRemove: optioanl; default is false
    • true: remove all the matches
    • false: remove only the first match

  // list: [1, 2, 2, 2, 5]
  list.remove(2);         // returns 4; returns the new length of the list
  // output: [1, 2, 2, 5]
  list.remove(2, true);   // returns 2
  // output: [1, 5]

• reverse(): reverse the list (modifies the original list)

  // list: [1, 2, 3, 4, 5]
  list.reverse();     // returns the pointer to the current list
  // output: [5, 4, 3, 2, 1]

• getReversedValue(): returns the array of list value in reversed order (doesn't modify the original list)

  // list: [1, 2, 3, 4, 5]
  const reverseValueArray = list.getReversedValue();     // returns the array
  // reverseValueArray: [5, 4, 3, 2, 1]
  // but the list is still the same

• sort(shouldReturn?): sort the list

  • shouldReturn: optional; default is false
    • true: returns the pointer to the current list (sorted)
    • false: return 'true' in case of successful sort

  // list: [3, 5, 1, 2, 4]
  list.sort();     // returns true
  // output: [1, 2, 3, 4, 5]

• isEqual(anotherLinkedList): checks whether list is equal with provided list or not

  • anotherLinkedList: an another instance of the LinkedList class

  // list: [1, 2, 3]
  // anotherList: [1, 2, 3]
  let isEqual = list.isEqual(anotherList);
  // isEqual: true
  list.push(4);
  isEqual = list.isEqual(anotherList);
  // isEqual: false

• merge(anotherLinkedList): merge the another linkedlist

  • anotherLinkedList: an another instance of the LinkedList class

  // list: [1, 2, 3]
  // anotherList: [4, 5]
  list.merge(anotherList);        // returns 5; returns the new length of the list
  // list: [1, 2, 3, 4, 5]

• node(value): returns the node with the provided value which can be used to create the new list path from any node

  // list: [1, 2, 4]
  const node = list.node(3);
  list.insert(2, node);
  console.log(list.JSON());
  /*
  {
      head: {
          value: 1, next: {
              value: 2, next: {
                  value: { value: 3, next: null },
                  next: { value: 4, next: null }
              }
          }
      },
      tail: { value: 4, next: null },
      lengthOfList: 4
  }
  */