Implement the following operations of a stack using queues.
push(x) -- Push element x onto stack.
pop() -- Removes the element on top of the stack.
top() -- Get the top element.
empty() -- Return whether the stack is empty.
Example:
MyStack stack = new MyStack();
stack.push(1);
stack.push(2);
stack.top(); // returns 2
stack.pop(); // returns 2
stack.empty(); // returns false
Notes:
You must use only standard operations of a queue -- which means only push to back, peek/pop from front, size, and is empty operations are valid.
Depending on your language, queue may not be supported natively. You may simulate a queue by using a list or deque (double-ended queue), as long as you use only standard operations of a queue.
You may assume that all operations are valid (for example, no pop or top operations will be called on an empty stack).
My code:
class MyStack(object):
def __init__(self):
self.dumbQueue = []
def push(self, x):
self.dumbQueue.append(x)
def pop(self):
value=self.dumbQueue[-1]
self.dumbQueue=self.dumbQueue[:-1]
return value
def top(self):
top = self.dumbQueue[-1]
return top
def empty(self):
return True if not self.dumbQueue else False
# Your MyStack object will be instantiated and called as such:
# obj = MyStack()
# obj.push(x)
# param_2 = obj.pop()
# param_3 = obj.top()
# param_4 = obj.empty()Solution: https://leetcode.com/problems/implement-stack-using-queues/