feat: added Lesson12's Java and Typescript files for Chelsea

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

@@ -7,6 +7,24 @@ 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 oddPoints = 0;
+    int evenPoints = 0;
+
+    for (ListNode current = head;
+        current != null && current.next != null;
+        current = current.next.next) {
+      if (current.val > current.next.val) {
+        evenPoints++;
+      } else {
+        oddPoints++;
+      }
+    }
+    if (oddPoints > evenPoints) {
+      return "Odd";
+    } else if (evenPoints > oddPoints) {
+      return "Even";
+    } else {
+      return "Tie";
+    }
   }
 }

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

@@ -9,18 +9,28 @@ public Stack() {
   }
 
   public void push(int value) {
-    // Your code here
+    ListNode newNode = new ListNode(value);
+    newNode.next = top;
+    top = newNode;
   }
 
   public int pop() {
-    return 0;
+    if (isEmpty()) {
+      throw new IllegalStateException("Stack is empty");
+    }
+    int value = top.val;
+    top = top.next;
+    return value;
   }
 
   public int peek() {
-    return 0;
+    if (isEmpty()) {
+      throw new IllegalStateException("Stack is empty");
+    }
+    return top.val;
   }
 
   public boolean isEmpty() {
-    return true;
+    return top == null;
   }
 }

lesson_12/structs_ts/package.json

@@ -34,6 +34,5 @@
     "tsc-watch": "^6.2.0",
     "typescript": "^5.6.2",
     "typescript-eslint": "^8.7.0"
-  },
-  "dependencies": {}
+  }
 }

lesson_12/structs_ts/src/lesson12.ts

@@ -6,6 +6,25 @@ 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 oddPoints = 0;
+    let evenPoints = 0;
+    let current: ListNode | null = head;
+
+    while (current && current.next) {
+      if (current.val > current.next.val) {
+        evenPoints++;
+      } else {
+        oddPoints++;
+      }
+      current = current.next.next || null;
+    }
+
+    if (oddPoints > evenPoints) {
+      return 'Odd';
+    } else if (evenPoints > oddPoints) {
+      return 'Even';
+    } else {
+      return 'Tie';
+    }
   }
 }

lesson_12/structs_ts/src/stack.ts

@@ -8,18 +8,28 @@ 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');
+    if (this.top === undefined) {
+      return undefined;
+    }
+    const poppedNode = this.top;
+    this.top = this.top.next;
+    return poppedNode.val;
   }
 
   peek(): number | null {
-    throw new Error('Not implemented');
+    if (this.top === undefined) {
+      throw new Error('Stack is empty');
+    }
+    return this.top.val;
   }
 
   isEmpty(): boolean {
-    throw new Error('Not implemented');
+    return this.top === undefined;
   }
 }