Stack
A stack is a data structure that follows the Last In First Out (LIFO) principle. It allows for the addition and removal of elements in a particular order, where the last element added is the first to be removed.
Space Complexity: O(n)
Time Complexity: O(1) for push/pop
Best Case: Ω(1)
Average Case: Θ(1)
Worst Case: O(1)
class Stack:
def __init__(self):
self.items = []
def push(self, item):
self.items.append(item)
def pop(self):
if not self.items:
return None
return self.items.pop()
def peek(self):
if not self.items:
return None
return self.items[-1]
def is_empty(self):
return len(self.items) == 0
def display(self):
return ' -> '.join(map(str, self.items))
# Example Usage
stack = Stack()
for i in range(20):
stack.push(random.randint(0, 100))
print(stack.display())