Detect Alternating Pattern

Code

#include <stdio.h>

int is_alternating_pattern(int *mem, int k) {
    // Write your pointer logic here
    // implicit assumption k <= n
    int i, *ptr;
    ptr = mem;

    for (i=0; i < k; i++) {
        if( (i < (k-2)) && ((*ptr) != (*(ptr+2)) )) {
            return 0;
        }
        ptr++;
    }
    return 1;
}

int main() {
    int n, k, arr[100];
    scanf("%d %d", &n, &k);

    for (int i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    int res = is_alternating_pattern(arr, k);
    printf("%d", res);

    return 0;
}

Solving Approach

implicit assumption k <= n

return at the first time an element is not the same as its (next +1)

also you'r limited by the size k, so stop at (k-2)