Classe coda, usa list

La classe Queue utilizza una lista

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

    def enqueue(self, x): self._lista.insert(0, x)

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

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

Test 1

coda=Queue()           # []

coda.enqueue(18)       # [18] 
coda.enqueue(1)        # [1, 18] 
coda.enqueue(28)       # [28, 1, 18]

print(coda.is_empty()) #             False
print(coda.dequeue())  # [28, 1]     18

print(coda.is_empty()) #             False
print(coda.dequeue())  # [28]        1

print(coda.is_empty()) #             False
print(coda.dequeue())  # []          28

print(coda.is_empty()) #             True

Test 2

coda=Queue()                       # []

for x in range(5):                 
    coda.enqueue(x)
print(coda._lista)                 # [4, 3, 2, 1, 0]

while(not coda.is_empty()): 
    print(coda.dequeue(), end=" ") # 0 1 2 3 4
print()
print(coda._lista)                 # []

Continua…

Aggiungi i metodi

  • x <– top(), il primo elemento inserito?
  • x <– bottom(), l’ultimo elemento inserito?
  • n <– size(), quanti elementi contiene la coda?