241. Different Ways to Add Parentheses

Given a string of numbers and operators, return all possible results from computing all the different possible ways to group numbers and operators. The valid operators are 

+

, 

-

 and 

*

.

Example 1
Input: 

"2-1-1"

.

((2-1)-1) = 0
(2-(1-1)) = 2

Output: 

[0, 2]

Example 2
Input: 

"2*3-4*5"

(2*(3-(4*5))) = -34
((2*3)-(4*5)) = -14
((2*(3-4))*5) = -10
(2*((3-4)*5)) = -10
(((2*3)-4)*5) = 10

Output: 

[-34, -14, -10, -10, 10]

class Solution(object):
def diffWaysToCompute(self, input):
"""
:type input: str
:rtype: List[int]
"""
L = []
for i in input:
if i.isdigit() == 0:
left = diffWaysToCompute(input[:input.index(i)+1])
right = diffWaysToCompute(input[input.index(i)+1:])
for n in left:
for m in right:
if i == '+':
L.append(n + m)
elif i == '-':
L.append(n - m)
elif i == '*':
L.append(n * m)
if L.count() == 0:
L.append(int(input))
return L
过不了编译就很气（c++代码可以过）

Line 11: NameError: global name 'diffWaysToCompute' is not defined

为什么啊