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]
A: (2*3)-4*5
((2*3)-4)*5=>1
(2*3)-(4*5)=>2
B:
2*(3-4)*5
(2*(3-4))*5=>1
2*((3-4)*5)=>2
"""
import re
tokens = re.split('(\D)', input)
nums = map(int, tokens[::2])
ops = map({'+': operator.add, '-': operator.sub, '*': operator.mul}.get, tokens[1::2])
def build(lo, hi):
if lo == hi:
return [nums[lo]]
ans = []
for i in range(lo, hi):
for a in build(lo, i):
for b in build(i+1, hi):
ans.append(ops[i](a, b))
return ans
return build(0, len(ops))
re.split("(\D)", "2+3-1")
['2', '+', '3', '-', '1']