feat: edited methods for Lesson12.java and Stack.java

Author: jjcapparell

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

@@ -2,11 +2,63 @@
 
 public 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 String gameResult(ListNode head) {
-    return null;
+    int score_even = 0;
+    int score_odd = 0;
+    int evenNum = 0;
+    int oddNum = 0;
+    for (int i=0;i<getLength(head);i++){
+      if (i%2==0){
+        ListNode resultNode = getElementAt(head, i);
+        evenNum = resultNode.val;
+      }
+      else if (i%2==1){
+        ListNode resultNode = getElementAt(head, i);
+        oddNum = resultNode.val;
+        if(evenNum>oddNum){
+        score_even+=1;
+        }
+        else if(evenNum<oddNum){
+        score_odd+=1;
+        }
+      }
+    }
+    if (score_even>score_odd){
+      return "Even";
+    }
+    else if (score_even<score_odd){
+      return "Odd";
+    }
+    else {
+      return "Tie";
+    }
+  }
+
+  public ListNode getElementAt(ListNode head, int position) {
+    ListNode current = head;
+    int index = 0;
+
+    // Traverse the list until reaching the desired position
+    while (current != null) {
+        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 null; // Return null if the position is out of bounds
+  }
+
+  public int getLength(ListNode head) {
+    int length = 0;
+    ListNode current = head;
+    
+    while (current != null) {
+        length++; // increment to keep count through each element
+        current = current.next; // moves on to next element
+    }
+    
+    return length;
   }
 }

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

@@ -9,18 +9,27 @@ public Stack() {
   }
 
   public void push(int value) {
-    // Your code here
+    ListNode newNode = new ListNode(value, 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;
   }
 }