为什么它返回一个空列表?
def count_smileys(arr):
stack = []
for i in range(len(arr)):
for j in range(i):
if arr[i][j] == ":" or arr[i][j] == ";":
stack.append(arr[i][j])
elif arr[i][j] == "~" or arr[i][j] == "-":
if stack == 0:
return False
else:
stack.append(arr[i][j])
elif arr[i][j] == "D" or arr[i][j] == ")":
if stack == 0:
return False
else:
stack.append(arr[i][j])
return stack
print(count_smileys([':D',':~)',';~D',':)'])) #, 4
print(count_smileys([':)',':(',':D',':O',':;'])) #, 2
print(count_smileys([';]', ':[', ';*', ':$', ';-D'])) #, 1

