Classe stack, usa list

di

Classe

La nuovo struttura dati utilizza una lista (list)

class Stack:
    def __init__(self): self._lista=[]

    def push(self, x):  self._lista.append(x)

    def pop(self):      return self._lista.pop()

    def is_empty(self): return (len(self._lista) == 0)

Test 1

stack=Stack()            # []

stack.push(18)           # [18]
stack.push(1)            # [18, 1]
stack.push(28)           # [18, 1, 28]

print(stack.is_empty())  #             False
print(stack.pop())       # [18, 1]     28

print(stack.is_empty())  # False
print(stack.pop())       # [18]        1

print(stack.is_empty())  # False
print(stack.pop())       # []          18

print(stack.is_empty())  #             True

Test 2

stack=Stack()                    # []
for x in range(5):         
    stack.push(x)
print(stack._lista)              # [0, 1, 2, 3, 4]

while(not stack.empty()):  
    print(stack.pop(), end=" ")  # 4 3 2 1 0
print()
print(stack._lista)              # []

Continua…

  1. x <– top(), l’elemento in cima allo stack
  2. n <– size(), quanti elementi contiene?