Feat: Adds, NileJackson's extra credit for Lesson12.ts

lesson_12/structs_ts/src/lesson12.ts

@@ -6,6 +6,27 @@ export class Lesson12 {
    * https://github.com/yang-su2000/Leetcode-algorithm-practice/tree/master/3062-winner-of-the-linked-list-game
    */
   public gameResult(head: ListNode | null): string {
-    return '';
+    if (!head) return 'Tie';
+
+    let current: ListNode | null = head;
+    const scores: number[] = [0, 0];
+
+    while (current && current.next) {
+      if (current.val !== current.next.val && current.val % 2 == 0) {
+        if (current.val > current.next.val) {
+          scores[0]++;
+        } else {
+          scores[1]++;
+        }
+      }
+      current = current.next;
+    }
+    if (scores[0] > scores[1]) {
+      return 'Even';
+    } else if (scores[0] < scores[1]) {
+      return 'Odd';
+    } else {
+      return 'Tie';
+    }
   }
 }

lesson_12/structs_ts/src/stack.ts

@@ -1,3 +1,4 @@
+/* eslint-disable @typescript-eslint/no-non-null-assertion */
 import { ListNode } from './list_node.js';
 
 export class Stack {
@@ -7,19 +8,27 @@ export class Stack {
     this.top = undefined;
   }
 
-  push(value: number): void {
-    throw new Error('Not implemented');
+  push(val: number): void {
+    const newNode = new ListNode(val);
+    newNode.next = this.top;
+    this.top = newNode;
   }
 
   pop(): number | undefined {
-    throw new Error('Not implemented');
+    if (this.isEmpty()) return undefined;
+    const val = this.top!.val;
+    this.top = this.top!.next;
+    return val;
   }
 
-  peek(): number | null {
-    throw new Error('Not implemented');
+  peek(): number {
+    if (this.isEmpty()) {
+      /* empty */
+    }
+    return this.top!.val;
   }
 
   isEmpty(): boolean {
-    throw new Error('Not implemented');
+    return this.top === undefined;
   }
 }