# WIPL - Editorial

I read your whole blog its Great thank you for this, but can u please explain the part u did * a| b* and then fill the values in dp array inshort the last part of that function.

I replied on your comment. Go take a look.

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Your approach is greedy. But in some problems greedy wonât land you global optimum, therefore dp comes in.

Like in âstandard coin change problemâ if we try to make a change, firstly using large denominations then going for less, this is greedy approach and wonât always give you minimum coins you need to pick.

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A little bit different DP approach by me

I just wanted to ask if there is a difference if we take to fill the DP array from top to bottom style rather than bottom-up. Is there a difference between both?

There should be no difference. You can use recursion and fill the dp[][] top to bottom

the code is only running for subtask 1, i don,t think this question can be done using greedy.

I recommend solving Dividing Coins problem. I used solution to this as a subpart of WIPL.

I was going through solutions section to see what are the different approach to solve this problem and I got this one https://www.codechef.com/viewsolution/41059309 . I guess he used bitmasking but I am not getting the logic. Can anyone explain ? @sksama @shivam51

Okay. Got it now. Thanks.

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Very good explanation. I was also thinking of this problem as a subset sum problem but couldnât figure out how to implement.

I have done using brutefore but used sets so repetitive calculations are avoided.
https://www.codechef.com/viewsolution/41519501

https://www.codechef.com/viewsolution/41692894
Did this using recursion, greedy. Doesnât pass all the test cases though.

This is a bitset implementation of subset sum problem. Itâs a standard thing that was mentioned in the editorial as well. Even I learnt this technique after this contest only.
Refer to Gfg page for better explanation, it might take little time to digest but itâs one of the most efficient ways to implement subset sum

https://www.codechef.com/viewsolution/41696157
This is my code for watching CPL problem,its kind of bruteforce approach,can anyone tell me which test case it is not passing,it will be a great help

Hello,can you please tell me which test case are not passing in my approach or whats wrong with my approach
Code:Solution: 41696157 | CodeChef

A different approach using bfs.