Yup, nothing smart here. Just sort the array and see if two adjacent elements are the same.

```
int compar(const void * i1, const void * i2);
bool containsDuplicate(int * nums, int numsSize)
{
int i, j;
qsort(nums, numsSize, sizeof(nums[0]), compar);
for (i = 0, j = numsSize - 1; i < j; ++i)
if (nums[i] == nums[i + 1])
return true;
return false;
}
int compar(const void * i1, const void * i2)
{
return *(const int *)i1 - *(const int *)i2;
}
```