feat: extra credit: typescript implementations added

Author: jjcapparell

lesson_12/structs_ts/src/lesson12.ts

@@ -1,11 +1,61 @@
 import { ListNode } from './list_node.js';
 
 export class Lesson12 {
-  /**
-   * Provide the solution to LeetCode 3062 here:
-   * https://github.com/yang-su2000/Leetcode-algorithm-practice/tree/master/3062-winner-of-the-linked-list-game
-   */
-  public gameResult(head: ListNode | null): string {
-    return '';
+  public gameResult(head: ListNode): string {
+    let scoreEven = 0;
+    let scoreOdd = 0;
+    let evenNum = 0;
+    let oddNum = 0;
+    const length = this.getLength(head);
+
+    for (let i = 0; i < length; i++) {
+      const resultNode = this.getElementAt(head, i);
+      if (resultNode) {
+        if (i % 2 === 0) {
+          evenNum = resultNode.val;
+        } else {
+          oddNum = resultNode.val;
+          if (evenNum > oddNum) {
+            scoreEven += 1;
+          } else if (evenNum < oddNum) {
+            scoreOdd += 1;
+          }
+        }
+      }
+    }
+
+    if (scoreEven > scoreOdd) {
+      return "Even";
+    } else if (scoreEven < scoreOdd) {
+      return "Odd";
+    } else {
+      return "Tie";
+    }
+  }
+
+  getElementAt(head: ListNode | undefined, position: number): ListNode | undefined {
+    let current = head;
+    let index = 0;
+
+    while (current !== undefined) {
+      if (index === position) {
+        return current; // Return the node at the specified position
+      }
+      current = current.next; // Move to the next node
+      index++; // Increment the index
+    }
+
+    return undefined; // Return null if the position is out of bounds
+  }
+
+  getLength(head: ListNode | undefined): number {
+    let length = 0;
+    let current = head;
+
+    while (current !== undefined) {
+      length++; // Increment to keep count through each element
+      current = current.next; // Move on to the next element
+    }
+    return length;
   }
 }

lesson_12/structs_ts/src/stack.ts

@@ -1,25 +1,34 @@
 import { ListNode } from './list_node.js';
 
 export class Stack {
-  private top: ListNode | undefined;
+  private top?: ListNode;
 
   constructor() {
     this.top = undefined;
   }
 
   push(value: number): void {
-    throw new Error('Not implemented');
+    const newNode = new ListNode(value, this.top);
+    this.top = newNode;
   }
 
-  pop(): number | undefined {
-    throw new Error('Not implemented');
+  pop(): number {
+    if (this.isEmpty()) {
+      throw new Error("Stack is empty");
+    }
+    const value = this.top!.val; // Non-null assertion since we've checked for emptiness
+    this.top = this.top?.next; // No change needed here, TypeScript allows accessing next
+    return value;
   }
 
-  peek(): number | null {
-    throw new Error('Not implemented');
+  peek(): number {
+    if (this.isEmpty()) {
+      throw new Error("Stack is empty");
+    }
+    return this.top!.val; // Non-null assertion since we've checked for emptiness
   }
 
   isEmpty(): boolean {
-    throw new Error('Not implemented');
+    return this.top === undefined; // Check for undefined since top is optional
   }
 }