Nice Kata but a bit easy for 5

You need to return a free-able string.
I added an approproate note to the solution setup.

In C, although it passes the fixed tests, it fails at random ones with the following error message:

Test Crashed
Caught unexpected signal: 6

free(): invalid pointer

Also most likely not a kata issue.

you should be adding larger values than 2

counter-example; +2 -1 -1 +2 -1 -1 +1 -1 +1 -1 = 0; but the path is invalid;

?

essessnsns?

definately best practise

for the LCM, both recursion and iteration would work; but i'm not sure why you think you'd need a hash table ?

so an iterative way would work?

No. No reason why you would need to.

Without your code, it is very difficult to help you, refer to the Troubleshooting guide about how to properly post it here.