241. Different Ways to ADD parentheses

Topic:

Given A string of numbers and operators, return all possible results from computing all the different possible ways to Gro Up numbers and operators. The valid operators + are, - and * .

Example 1

Input: "2-1-1" .

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

Output:[0, 2]

Example 2

Input:"2*3-4*5"

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

Output:[-34, -14, -10, -10, 10]

Links: http://leetcode.com/problems/different-ways-to-add-parentheses/

Exercises

This is said to be different Ways to add parentheses, in fact, the meaning is to ignore the operator's priority to calculate the formula. Our solution is: In the case of valid, as long as the operator is encountered, we calculate the number on the left and the right, and then according to the operator to get the result. When looking at discuss, I found Stefan Pochmann the solution of the great God ... One line, rub, this dude Rubik's Cube also play very well, is said to have won the German Rubik's Cube game first, is true cow.

Time Complexity-o (3n), Space complexity-o (3n)

 Public classSolution { PublicList<integer>diffwaystocompute (String input) {if(Input = =NULL|| Input.length () = = 0)            return NewArraylist<integer>(); List<Integer> res =NewArraylist<>();  for(inti = 0; I < input.length (); i++) {            Charc =Input.charat (i); if(c = = ' + ' | | c = = ' * ' | | c = = '-') {List<Integer> L1 = diffwaystocompute (input.substring (0, i)); List<Integer> L2 = Diffwaystocompute (input.substring (i + 1));  for(intx:l1) {                     for(inty:l2) {                        if(c = = ' + ')) Res.add (x+y); Else if(c = = '-')) Res.add (x-y); ElseRes.add (x*y); }                }            }        }                if(res.size () = = 0) Res.add (integer.valueof (input)); returnRes; }}

Reference:

Https://leetcode.com/discuss/48468/1-11-lines-python-9-lines-c

Https://leetcode.com/discuss/60626/share-a-clean-and-short-java-solution

Https://leetcode.com/discuss/53566/python-easy-to-understand-solution-divide-and-conquer

Https://leetcode.com/discuss/61840/java-recursive-9ms-and-dp-4ms-solution

Https://leetcode.com/discuss/48477/a-recursive-java-solution-284-ms

Https://leetcode.com/discuss/48488/c-4ms-recursive-%26-dp-solution-with-brief-explanation

Https://leetcode.com/discuss/48494/what-is-the-time-complexity-of-divide-and-conquer-method

Https://leetcode.com/discuss/55255/clean-ac-c-solution-with-explanation

241. Different Ways to ADD parentheses