Bağlantılı Listeyi kullanarak yığınlama

def execute_stack_linked_list_opt(operations):
    class StackNode:
        def __init__(self, val=0, next=None):
            self.val = val
            self.next = next
            
    head = None
    popped = []
    for op in operations:
        if op[0] == "push":
            new_node = StackNode(op[1], head)
            head = new_node
        elif op[0] == "pop":
            if not head:
                popped.append(None)
            else:
                popped.append(head.val)
                head = head.next
    return popped

def execute_stack_linked_list_brute(operations):
    # Simulates stack using list
    s = []
    res = []
    for op in operations:
        if op[0] == "push":
            s.append(op[1])
        elif op[0] == "pop":
            res.append(s.pop() if s else None)
    return res