There's some kind of memory issue when running in C, i get this STDERR message quite randomly. I really don't think I'm the one responsible, because the sole memory handling operation I do is a simple malloc ("out = (char*) malloc(len*sizeof(char)+1);")

STDERR:
*** Error in `/home/codewarrior/solution': free(): invalid next size (fast): 0x0000000000f7e850 ***

My code passed the sample tests but won't go through the actual attempt. It says "Time: 17ms Passed: 4 Failed: 1 Errors: 1".