feat: added Stack impl/ LeetCode 3062 finished in TypeScript - Xavier Cruz

lesson_12/structs_ts/src/lesson12.ts

@@ -6,6 +6,32 @@ 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 e_pts = 0;
+    let o_pts = 0;
+
+    if (head === null) {
+      return '';
+    }
+
+    let curr: ListNode | undefined = head;
+
+    while (curr != null) {
+      const next: ListNode | undefined = curr.next;
+      if (next === undefined) {
+        return '';
+      }
+      if (curr.val > next?.val) {
+        e_pts++;
+      } else if (curr.val < next?.val) {
+        o_pts++;
+      }
+      curr = next.next;
+    }
+
+    if (e_pts === o_pts) {
+      return 'Tie';
+    }
+
+    return e_pts > o_pts ? 'Even' : 'Odd';
   }
 }

lesson_12/structs_ts/src/stack.ts

@@ -8,18 +8,39 @@ export class Stack {
   }
 
   push(value: number): void {
-    throw new Error('Not implemented');
+    const node: ListNode | undefined = new ListNode(value);
+
+    node.next = this.top;
+    this.top = node;
   }
 
   pop(): number | undefined {
-    throw new Error('Not implemented');
+    if (this.isEmpty()) {
+      throw new Error('Stack is empty');
+    }
+
+    if (this.top) {
+      const value_to_pop: number = this.top.val;
+      this.top = this.top.next;
+      return value_to_pop;
+    }
+
+    return undefined;
   }
 
   peek(): number | null {
-    throw new Error('Not implemented');
+    if (this.isEmpty()) {
+      throw new Error('Stack is empty');
+    }
+
+    if (this.top) {
+      return this.top.val;
+    }
+
+    return null;
   }
 
   isEmpty(): boolean {
-    throw new Error('Not implemented');
+    return top === undefined;
   }
 }