To find common elements( matching elements) between the arrays - c

Question

Consider if I am having an input, where number of arrays to have as input is not fixed and the number of elements in each array is also not fixed. So each time my input varies,
Example 1: 1st input
1st array= [2,3,4]
2nd array =[6,7,8,9]
3rd array=[5,3,12]
Example 2: 2nd input
1st array= [6,3,4,8]
2nd array =[6,7,4,9]
3rd array=[1,2,12]
4th array= [20,21,22,23,25]
The solution required is, 1st array is considered as a reference array, the next set of arrays are to be checked with respect to the first array(reference), the requirement is second array should not have a common element with respect to first array and it goes on for next check third array should not have a common element with first array.
from 1st Example
1st array= [2,3,4] -- reference array
1st array= [2,3,4] is compared to 2nd array =[6,7,8,9]
1st array= [2,3,4] is compared to 3rd array=[5,3,12]
solution needed:
+ print 1st array( reference array)
+ if no common elements found between 1st array and 2nd array, from ex. no common elements found, so print out the 2nd array.
+ same for 3rd array, from ex. there is common element(3 is present in both first and third array), so dont print.
I ave tried this by storing the input in 2-dimensional array, but i messed up .
Please guide me for computing this with your algorithm/code.

Answer 1

Notice how i had to create an array to contain the length of the various arrays, and a parameter to tell how long that array is.
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
void print_array(int *a, int size) {
int i;
for (i = 0; i<size; i++) {
printf("%d ", a[i]);
}
printf("\n");
}
bool is_in(int *a, int size, int elem) {
int i;
for (i=0; i<size; i++) {
if (a[i] == elem) {
return true;
}
}
return false;
}
void f(int **a, int a_siz, int* sizes) {
print_array(a[0],sizes[0]);
for (int i=1; i< a_siz; i++) {
bool common_element = false;
for (int k=0; k< sizes[i]; k++) {
if (is_in(a[0],sizes[0],a[i][k])) {
common_element = true;
break;
}
}
if (! common_element) {
print_array(a[i],sizes[i]);
}
}
}
int main() {
int s = 3;
int sizes[] = {3,4,3};
int **a = malloc(sizeof(int*)*3);
for (int i=0; i<s; i++) {
a[i] = malloc(sizeof(int*)*sizes[i]);
}
a[0][0] = 2;
a[0][1] = 3;
a[0][2] = 4;
a[1][0] = 4;
a[1][1] = 7;
a[1][2] = 8;
a[1][3] = 9;
a[2][0] = 5;
a[2][1] = 44;
a[2][2] = 12;
f(a,s,&sizes);
}

Answer 2

Since the question states that the length of the array is not a constant, the idea of static 2-dimensional array might not work. You can go with creating a 2 dimensional array using DMA (malloc and calloc functions)
You can prefer a straight forward algorithm which compares each element in reference array with other arrays.