-
Notifications
You must be signed in to change notification settings - Fork 0
/
stack.py
49 lines (39 loc) · 1010 Bytes
/
stack.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
class Node:
def __init__(self, data=None) -> None:
self.data = data
self.next = None
class Stack:
def __init__(self, data=None) -> None:
self.head = Node(data)
self._size = 0
def __str__(self) -> str:
current = self.head
out = ""
while current:
out += str(current.data) + " -> "
current = current.next
return out[:-4]
def isEmpty(self):
return self._size == 0
def size(self):
return self._size
def top(self):
return self.head.data
def push(self, item):
node = Node(item)
node.next = self.head
self.head = node
self.size += 1
def pop(self):
if self.isEmpty():
raise Exception("Popping from an empty stack")
data = self.head.data
self.head = self.head.next
self.size -= 1
return data
stack = Stack(3)
stack.push(1)
stack.push(2)
print(stack)
print(stack.pop())
print(stack)