Merge pull request #574 from AnirudhPhophalia/patch-4

Implement LinkedList class with basic operations using Typescript

Author: Pradeepsingh61

TypeScript/data_structures/linkedLists/linkedLists.ts

@@ -0,0 +1,117 @@
+class Node<T> {
+  value: T;
+  next: Node<T> | null = null;
+  constructor(value: T) {
+    this.value = value;
+  }
+}
+
+class LinkedList<T> {
+  private head: Node<T> | null = null;
+  private length: number = 0;
+
+  append(value: T): void {
+    const newNode = new Node(value);
+    if (!this.head) {
+      this.head = newNode;
+    } else {
+      let current = this.head;
+      while (current.next) {
+        current = current.next;
+      }
+      current.next = newNode;
+    }
+    this.length++;
+  }
+
+  prepend(value: T): void {
+    const newNode = new Node(value);
+    newNode.next = this.head;
+    this.head = newNode;
+    this.length++;
+  }
+
+  insertAt(index: number, value: T): void {
+    if (index < 0 || index > this.length) return console.log("Invalid index");
+    if (index === 0) return this.prepend(value);
+    if (index === this.length) return this.append(value);
+
+    const newNode = new Node(value);
+    let current = this.head;
+    let prev: Node<T> | null = null;
+    let i = 0;
+    while (i < index && current) {
+      prev = current;
+      current = current.next;
+      i++;
+    }
+    if (prev) {
+      newNode.next = current;
+      prev.next = newNode;
+      this.length++;
+    }
+  }
+
+  remove(value: T): void {
+    if (!this.head) return;
+
+    if (this.head.value === value) {
+      this.head = this.head.next;
+      this.length--;
+      return;
+    }
+
+    let current = this.head;
+    let prev: Node<T> | null = null;
+    while (current && current.value !== value) {
+      prev = current;
+      current = current.next;
+    }
+
+    if (current && prev) {
+      prev.next = current.next;
+      this.length--;
+    }
+  }
+
+  search(value: T): number {
+    let current = this.head;
+    let index = 0;
+    while (current) {
+      if (current.value === value) return index;
+      current = current.next;
+      index++;
+    }
+    return -1;
+  }
+
+  printList(): void {
+    let current = this.head;
+    let result = "";
+    while (current) {
+      result += current.value + " -> ";
+      current = current.next;
+    }
+    console.log(result + "null");
+  }
+
+  size(): number {
+    return this.length;
+  }
+
+  isEmpty(): boolean {
+    return this.length === 0;
+  }
+}
+
+// Example usage:
+const list = new LinkedList<number>();
+list.append(1);
+list.append(2);
+list.append(3);
+list.prepend(0);
+list.printList(); // Output: 0 -> 1 -> 2 -> 3 -> null
+console.log(list.search(2)); // Output: 2
+list.remove(1);
+list.printList(); // Output: 0 -> 2 -> 3 -> null
+console.log(list.size());    // Output: 3