feat: Add lesson_12 and Extra Credit Solutions for Tommy Tran

lesson_12/structs_java/structs_app/src/main/java/com/codedifferently/lesson12/Lesson12.java

@@ -7,6 +7,22 @@ public class Lesson12 {
    * https://github.com/yang-su2000/Leetcode-algorithm-practice/tree/master/3062-winner-of-the-linked-list-game
    */
   public String gameResult(ListNode head) {
-    return null;
+    int even = 0;
+    int odd = 0;
+    while (head != null && head.next != null) {
+      if (head.val > head.next.val) {
+        even++;
+      } else {
+        odd++;
+      }
+      head = head.next.next;
+    }
+    if (even == odd) {
+      return ("Tie");
+    } else if (even > odd) {
+      return ("Even");
+    } else {
+      return ("Odd");
+    }
   }
 }

lesson_12/structs_java/structs_app/src/main/java/com/codedifferently/lesson12/Stack.java

@@ -10,17 +10,23 @@ public Stack() {
 
   public void push(int value) {
     // Your code here
+    ListNode top2 = new ListNode(value);
+    top2.next = top;
+    top = top2;
   }
 
   public int pop() {
-    return 0;
+    int topvalue = top.val;
+    top = top.next;
+
+    return topvalue;
   }
 
   public int peek() {
-    return 0;
+    return top.val;
   }
 
   public boolean isEmpty() {
-    return true;
+    return top == null;
   }
 }

lesson_12/structs_ts/src/lesson12.ts

@@ -6,6 +6,22 @@ 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 '';
+    let even = 0;
+    let odd = 0;
+    while (head != null && head.next != null) {
+      if (head.val > head.next.val) {
+        even++;
+      } else {
+        odd++;
+      }
+      head = head.next.next !== undefined ? head.next.next : null;
+    }
+    if (even === odd) {
+      return 'Tie';
+    } else if (even > odd) {
+      return 'Even';
+    } else {
+      return 'Odd';
+    }
   }
 }

lesson_12/structs_ts/src/stack.ts

@@ -8,18 +8,24 @@ export class Stack {
   }
 
   push(value: number): void {
-    throw new Error('Not implemented');
+    const newnode = new ListNode(value);
+    newnode.next = this.top;
+    this.top = newnode;
   }
 
   pop(): number | undefined {
-    throw new Error('Not implemented');
+    const nodevalue = this.top?.val;
+    this.top = this.top?.next;
+    return nodevalue;
   }
 
   peek(): number | null {
-    throw new Error('Not implemented');
+    if (this.top === undefined) {
+      throw new Error('is Empty');
+    }
+    return this.top ? this.top.val : null;
   }
-
   isEmpty(): boolean {
-    throw new Error('Not implemented');
+    return this.top === undefined;
   }
 }