/* Include lib */
#include <stdio.h>

/* Define */
#define ARRAY_MAX1      6
#define ARRAY_MAX2      8
#define ARRAY_MAX3      10

int array1[ARRAY_MAX1] = { 0, 1, 2, 3, 4, 5 };
int array2[ARRAY_MAX2] = { 9, 10, 2, 6, 7, 15, 2, 1 };
int array3[ARRAY_MAX3] = { 1, 8, 19, 20, 33, 12, 2, 1, 9, 43 };

/* API */
/* API linear search, return location >= 0 as soon as found. Otherwise return <= 0 */
int linear_search(int *arr, int size, int key)
{
    int i;
    
    if (!arr || size == 0) {
        printf("Wrong input !!\n");
        return -2;
    }
    
    for (i = 0; i < size; i++) {
        if (key == arr[i])
            return i;
    }
    
    return -1;
}

/* API count a value appear how many times in array */
int array_count_appearance(int *arr, int size, int key)
{
    int i, ret, pos, cnt = 0;
    
    if (!arr || size == 0) {
        printf("Wrong input !!\n");
        return -2;
    }
    
    pos = 0;
    do {
        ret = linear_search(&arr[pos], size, key);
        if (ret >= 0) {
            cnt++;
            pos = ret + 1;
            size = size - pos;
            if (size <= 0)
                break;
        }
    } while (ret >= 0);
    
    return cnt;
}


/* Main func interract with user */
int main()
{
#if 1 /* Method 1: array have limit elements */
    int common_found[ARRAY_MAX3] = { 0 };
    int common_size = 0;
    int i, cnt = 0;

    /* Loop each element in array1, linear search it in array 2, then array3. Count and jump next array if found */
    cnt = 0;
    for (i = 0; i < ARRAY_MAX1; i++) {
        cnt = 1;
        if (linear_search(&array2[0], ARRAY_MAX2, array1[i]) >= 0)
            cnt++;
        if (linear_search(&array3[0], ARRAY_MAX3, array1[i]) >= 0)
            cnt++;
            
        /* If it appears in 3 array, printout and store */
        if (cnt == 3) {
            printf("Found element value %d appears in %d arrays\n", array1[i], cnt);
            common_found[common_size++] = array1[i];
        }
    }

    /* With each store, find it repeated how many times in each array by linear search */
    for (i = 0; i < common_size; i++) {
        cnt = array_count_appearance(&array1[0], ARRAY_MAX1, common_found[i]);
        if (cnt >= 0)
            printf("Found element value %d appears %d times in ARRAY1\n", common_found[i], cnt);

        cnt = array_count_appearance(&array2[0], ARRAY_MAX2, common_found[i]);
        if (cnt >= 0)
            printf("Found element value %d appears %d times in ARRAY2\n", common_found[i], cnt);

        cnt = array_count_appearance(&array3[0], ARRAY_MAX3, common_found[i]);
        if (cnt >= 0)
            printf("Found element value %d appears %d times in ARRAY3\n", common_found[i], cnt);
    }
#endif

#if 0 /* Method 2: array have too many elements */

    /* Sort array or assume these array sorted before */
    
    /* Loop each element in array1, binary search it in array 2, then array3. Count and jump next array if found */
    
    /* If it appears in 3 array, printout and store */
    
    /* With each store, find it repeated how many times in each array by linear search */
#endif    
}