@Chrono79: thanks!

@S4ule, not, literally it says:

return NULL, or {-1, -1, -1} for C

your read it as:

return NULL or {-1, -1, -1}

The comma is there to separate both cases.

then return NULL, or {-1, -1, -1} for C

Means that generally you return NULL but {-1, -1, -1} for C language. Yes a bit too terse.
BTW you could have seen in "Sample Tests" this test:

int a2[3] = {-1, -1, -1};
dotest(820, 81, 550, a2);

which illustrates the case where "v1 >= v2".

That literally say "NULL or {-1, -1, -1}".

So why i need to return not null tab ?

Wtf bro.

(c)
If v1 >= v2 then return NULL, or {-1, -1, -1} for C.
The test part fail if i return NULL.

if (v1 >= v2)
return (NULL);
don't work

look at it this way:

"it works perfectly for all test cases [that happen to be the paritcular ones] on another compiler"

consider which tests appear here that are missing on this other compiler

it says it doesnt work but on another compiler it works perfectly for all test cases.

Fixed.

Fixed.

"between 1 and 50." but fixedTests() and randomTests() also include zero in c;