ah sorry, marked as resolved

Mostly fixed!

Fixed!

That's right

This solution is also in pseudo-polynomial time but it is optimized using bitwise operations, which makes it 64 times faster. Try to figure out why it works! :D

I don't think a greedy solution would work here... Consider arr = [3,6,7,9] and K = 10, a subset would be {7,3}. Let's look at all the conditions in your for loop:
len(res) != 0, so the first condition fails
total != 0, so the second condition fails
total - res[-1] (10 - 9) > 0, so the third condition (if) fails
total - res[-1] (10 - 9) != 0, so the third condition (elif) fails

Now from your else, total = 10 - 9 = 1
Since there is no 1 in the original array, your code will loop through the array and incorrectly output False.

Is it okay now?

Changing var to let fixed it.

Sorry i'm still quite unfamiliar, but how would input modification affect?

Thanks for the suggestion, now answers will be returned as BigInt.

Done. though i'm not sure where to use find_a(j[:],i)? Do i use it as the function?

[ 6, -24, -5, 18 ] 164
[ 3, 18, 14, 5 ] -357
[ 10, -3, -25, -10 ] 43
[ -9, -9, -20, -29 ] -132
[ -7, -4, 8, -18 ] -787
[ -17, 9, 15, -5 ] 129
[ -14, -11, -12, 5 ] -309
[ -25, 16, -3, 17 ] -632
[ -19, -9, -23, -1 ] -708
[ -9, -5, -16, -25 ] 169
[ -14, -19, 0, -9 ] 334
[ 19, -23, -26, -16 ] 201
[ -25, 20, -23, 14 ] 366
[ 7, 1, -29, -17 ] -315
[ 14, -19, -10, 12 ] -185
[ -22, 5, -1, -21 ] -171
[ 9, -6, 3, -2 ] -640
[ -27, -22, -8, -8 ] -457
[ -9, -19, 5, -28 ] -145
[ -27, 16, 2, 3 ] 457
[ 18, -22, 4, -26 ] -772

I've checked that they're not the same every time?

They should not the same every time. i've reduced to 100 random cases.

Changed the answers to string notation.