【LEETCODE】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]

参考：

http://bookshadow.com/weblog/2015/07/27/leetcode-different-ways-add-parentheses/

class Solution(object):    def diffWaysToCompute(self, input):        """        :type input: str        :rtype: List[int]        """                return [a+b if c=='+' else a-b if c=='-' else a*b            for i,c in enumerate(input) if c in '+-*'            for a in self.diffWaysToCompute(input[:i])            for b in self.diffWaysToCompute(input[i+1:])            ] or [int(input)]