BLOPER2  Operators (new ver)
Given a sequence a1, a2,..., an and a integer S, your task is find a way to insert an operator ‘+’ , ‘‘, ‘.‘, ‘~‘ to every neighbor pair of A, that the result of the expression after insert equal to S.
Note that :
 a . b = a + 2 * b
 a ~ b = a  2 * b
Input
First line : N and S (2 ≤ N ≤ 22, S ≤ 5 * 10^{16})
Second line : N integers, a1, a2,..., an (ai ≤ 10^{15})
Output
If there are way(s) to insert, output any of them, otherwise output “Impossible” (without quotes).
Example
Input: 9 5 1 2 3 4 5 6 7 8 9 Output: ~~~++++
Input: 3 1 2 5 7 Output: Impossible
Details:
In first test case : 1  2  2 * 3  2 * 4  2 * 5 + 6 + 7 + 8 + 9 = 5
You may want to try another version here.
hide comments
Rohit Agarwal:
20181118 16:55:52
@Kata: Hi! I have a query, my ideone submission for worst case take 836ms (22 elements and Impossible answer) and yet it times out here. How is that possible? Could you please explain it?


shubham9261:
20170730 09:31:57
there is not given any thing about precedence of operators:i.e,12~3=1~3 or 122*3????


sushantgokhale:
20170418 10:35:00
Kata, could u check ID19236413 ? I dont know which test case failing Last edit: 20170418 10:41:54 

pavan26:
20170317 05:04:59
can you check my code ?? ID 18993235 Last edit: 20170317 05:09:37 

pavan26:
20170317 05:00:46
Any test cases please!! 

san93st:
20160716 11:28:39
Input is not number of test case. I can't terminate my program. 

sushantgokhale:
20160601 15:13:22
Kata, could you publish the test cases? My code is failing after 15 or 16th test case. If you publish, I will be able to correct my code. It would be great help.


ISHANI:
20141125 23:44:10
Kata,


fitcat:
20141125 23:44:10
Are the following valid?

Added by:  Kata 
Date:  20140330 
Time limit:  1.5s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ASM64 