Ice Cream Parlor Hacker Rank Solution in C, Electronics Shop Hacker Rank Solution in C

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>

int main()
 {
    int m,n,t,i,j,flag;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d%d",&m,&n);
        int a[n];
        for(i=0;i<n;i++)
            scanf("%d",&a[i]);
        for(i=0;i<n;i++)
            for(j=i+1;j<n;j++)
                if(a[i]+a[j] == m)
                   printf("%d\t%d\n",i+1,j+1);
    }
    return 0;
}

Here in the above solution, we need to find all possible pairs in a single array. But if we need to find all possible pairs that can be formed with the elements from two different arrays then the j loop must start from 0.

Here is the example of such a problem

Problem: Electronics Shop

https://www.hackerrank.com/challenges/electronics-shop/problem

Solution:

#include<stdio.h>

int main()

{

    unsigned long long int b,n,m,i,j,ans=0;

    scanf("%llu%llu%llu",&b,&n,&m);

    int k[n],u[m];

    for(i=0;i<n;i++)

        scanf("%llu",&k[i]);

    for(i=0;i<m;i++)

        scanf("%llu",&u[i]);

    for(i=0;i<n;i++)

    {

        for(j=0;j<m;j++)

            if(k[i]+u[j] <= b && ans<k[i]+u[j])

                ans=k[i]+u[j];

    }

    if(ans == 0)

        printf("-1");

    else

        printf("%llu",ans);

}