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]

符號左邊部分與右邊部分分別計算， ?divide and conquer.