Lesson 4: Distinct (Distinct)

This is a simple problem.


First, we sort all the values, and then scan if there is any slot, the value of which is different from its previous slot.

Possibly, a bug can be caused if you forget to check corner cases: if N == 0 or N == 1, so we should return 0 or return 1, respectively.

int comparator(const void *a, const void *b)
{
    if (*(int*)a == *(int*)b){
        return 0;
    }
    
    if (*(int*)a < *(int*)b){
        return -1;
    }
    
    
    return 1;
}

int solution(int A[], int N) 
{
    if (N == 0){
        return 0;
    }
    
    qsort(A, N, sizeof(int), comparator);
    
    int cnt = 1;
    
    int i;    
    for (i = 1; i < N; i++){
        if (A[i - 1] != A[i]){
            cnt++;
        }
    }
    
    return cnt;
}