# BETWEEN-TWO-SETS hackerrank Solution - Correct, Optimal and Working

``````/*
*  Author: Arpit Bhayani
*  https://arpitbhayani.me
*/
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <climits>
#include <deque>
#include <iostream>
#include <list>
#include <limits>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <vector>

#define ll long long

#define MIN(a, b) a < b ? a : b
#define MAX(a, b) a > b ? a : b

using namespace std;

int i = 0;
char ch;
while((ch = getchar()) != '\n') {
str[i++] = ch;
}
str[i] = '\0';
return i;
}

int _gcd(int a, int b) {
if(b == 0) {
return a;
}
return _gcd(b, a % b);
}

int gcd(int a, int b) {
if(a > b) {
return _gcd(a, b);
}
return _gcd(b, a);
}

int lcm_2(int a, int b) {
return (int) ((ll int)(a) * (ll int)(b)) / gcd(a, b);
}

int lcm(int * arr, int n) {
int l = 1;
for(int i = 0 ; i < n; i++) {
l = lcm_2(arr[i], l);
}
return l;
}

int main(int argc, char *argv[]) {
int n, m;
int *arr1, *arr2;
scanf("%d%d", &n, &m);

arr1 = (int *) malloc(sizeof(int) * n);
arr2 = (int *) malloc(sizeof(int) * m);

for(int i = 0 ; i < n; i++) {
scanf("%d", &arr1[i]);
}

int minb = INT_MAX;
for(int i = 0 ; i < m; i++) {
scanf("%d", &arr2[i]);
minb = (arr2[i] < minb) ? arr2[i] : minb;
}

int lcma, count = 0;

lcma = lcm(arr1, n);

for(int i = lcma; i <= minb; i+= lcma) {
int all_check = 1;
for(int j = 0; j < m; j++) {
if(arr2[j] % i != 0) {
all_check = 0;
}
}
count += all_check;
}
printf("%d\n", count);

free(arr1);
free(arr2);

return 0;
}
``````