fix: getDuplicate() must not modify const numbers array

This commit is contained in:
Simon Wiesend 2025-12-07 17:48:50 +01:00
parent f1cffd33d8
commit 9394b51158
Signed by: wiesendsi102436
GPG Key ID: C18A833054142CF0

View File

@ -74,13 +74,27 @@ unsigned int *createNumbers(unsigned int len)
// Returns only the only number in numbers which is present twice. Returns zero on errors.
unsigned int getDuplicate(const unsigned int numbers[], unsigned int len)
{
qsort((void *)numbers, len, sizeof(int), compareInt); // sort the array
unsigned int *numbersCpy = malloc(sizeof(unsigned int) * len);
if (!numbersCpy)
{
return 0;
}
memcpy(numbersCpy, numbers, len * sizeof(unsigned int));
numbersCpy = numbersCpy; // shadow the numbers array with copy
qsort((void *)numbersCpy, len, sizeof(int), compareInt); // sort the array
unsigned int duplicateFound = 0; // zero on errors
for (int i = 0; i < len - 1; i++)
{
if (numbers[i] == numbers[i + 1])
return numbers[i];
if (numbersCpy[i] == numbersCpy[i + 1])
{
duplicateFound = numbersCpy[i];
break;
}
return 0; // zero on errors
}
free(numbersCpy);
return duplicateFound;
}
static int compareInt(const void *ptr1, const void *ptr2)