Steque.ts
For the full content of this gist, refer to https://gist.github.com/CodingAbdullah/f88d2b8db71df550c0f5581cddb1c8e3
McMaster. Software Engineer with a keen interest in blockchain and web3.
import { LinkedList } from '../LinkedLists/LinkedList';
// Steque implementation is a hybrid of Stack-Queue, implements LIFO principle at the front
// Supports Queue insertion at the back only (Enqueue)
// Implemented using a Singular Linked List
class Steque {
stequeList: LinkedList
constructor() {
this.stequeList = new LinkedList();
}
// Implement LIFO with the push and pop methods at the front of the Steque
// Add the item at the front
push(item: number): void {
this.stequeList.appendFirst(item);
}
// Remove the item at the front
pop(): number | null {
return this.stequeList.removeFirst();
}
// Enqueue at the end of the Steque
enqueue(item: number): void {
this.stequeList.appendLast(item);
}
// Peek at the front of the Steque
peekFront(): number | null {
if (this.stequeList.length() === 0) {
return null;
}
else {
let frontItem = this.stequeList.head;
return frontItem!.item;
}
}
// Peek at the back of the Steque
peekBack(): number | null {
if (this.stequeList.length() === 0) {
return null;
}
else {
let traverseNode = this.stequeList.head;
// Traverse to the end of the Steque
while (traverseNode!.next !== null) {
traverseNode = traverseNode!.next;
}
// Return the last item in the Steque
let backItem = traverseNode;
return backItem!.item;
}
}
// Return the length of the Steque
length(): number {
return this.stequeList.length();
}
}
export { Steque };