This commit is contained in:
Chahat Tekwani 2021-08-31 14:34:15 +05:30
parent 4548296aff
commit d19588e3da

View File

@ -1,67 +1,67 @@
import LinkedList from '../linked-list/LinkedList';
// import LinkedList from '../linked-list/LinkedList';
export default class Stack {
constructor() {
// We're going to implement Stack based on LinkedList since these
// structures are quite similar. Compare push/pop operations of the Stack
// with prepend/deleteHead operations of LinkedList.
this.linkedList = new LinkedList();
}
// export default class Stack {
// constructor() {
// // We're going to implement Stack based on LinkedList since these
// // structures are quite similar. Compare push/pop operations of the Stack
// // with prepend/deleteHead operations of LinkedList.
// this.linkedList = new LinkedList();
// }
/**
* @return {boolean}
*/
isEmpty() {
// The stack is empty if its linked list doesn't have a head.
return !this.linkedList.head;
}
// /**
// * @return {boolean}
// */
// isEmpty() {
// // The stack is empty if its linked list doesn't have a head.
// return !this.linkedList.head;
// }
/**
* @return {*}
*/
peek() {
if (this.isEmpty()) {
// If the linked list is empty then there is nothing to peek from.
return null;
}
// /**
// * @return {*}
// */
// peek() {
// if (this.isEmpty()) {
// // If the linked list is empty then there is nothing to peek from.
// return null;
// }
// Just read the value from the start of linked list without deleting it.
return this.linkedList.head.value;
}
// // Just read the value from the start of linked list without deleting it.
// return this.linkedList.head.value;
// }
/**
* @param {*} value
*/
push(value) {
// Pushing means to lay the value on top of the stack. Therefore let's just add
// the new value at the start of the linked list.
this.linkedList.prepend(value);
}
// /**
// * @param {*} value
// */
// push(value) {
// // Pushing means to lay the value on top of the stack. Therefore let's just add
// // the new value at the start of the linked list.
// this.linkedList.prepend(value);
// }
/**
* @return {*}
*/
pop() {
// Let's try to delete the first node (the head) from the linked list.
// If there is no head (the linked list is empty) just return null.
const removedHead = this.linkedList.deleteHead();
return removedHead ? removedHead.value : null;
}
// /**
// * @return {*}
// */
// pop() {
// // Let's try to delete the first node (the head) from the linked list.
// // If there is no head (the linked list is empty) just return null.
// const removedHead = this.linkedList.deleteHead();
// return removedHead ? removedHead.value : null;
// }
/**
* @return {*[]}
*/
toArray() {
return this.linkedList
.toArray()
.map((linkedListNode) => linkedListNode.value);
}
// /**
// * @return {*[]}
// */
// toArray() {
// return this.linkedList
// .toArray()
// .map((linkedListNode) => linkedListNode.value);
// }
/**
* @param {function} [callback]
* @return {string}
*/
toString(callback) {
return this.linkedList.toString(callback);
}
}
// /**
// * @param {function} [callback]
// * @return {string}
// */
// toString(callback) {
// return this.linkedList.toString(callback);
// }
// }