Question

Jojo is given N integers, A 1, A 2, ..., A N by his teacher. His teacher also give him an integer K and 2 M integers, L 1, L 2, ..., L M and R 1, R 2, ..., R M. For each i from 1 to M , his teacher asked him to calculate the sum of multiple of K index numbers from index L i to R i . For example if L i = 3 and R i = 10 and K = 3, then he has to calculate the value of ( A 3 + A 6 + A9). Help him by making the program to calculate it quickly!

Format Input:

The first line consist of three integers, N , M, and K. The second line consist of N integers, A 1, A 2, ..., A N . The next M lines consist of two integers, L i and R i.

Format Output:

Output M lines, the answer for L i and R i , where i is an integer from 1 to M.

Constraints

• 1 ≤ N, M ≤ 10⁵

• 1 ≤ A i ≤ 10² • 1 ≤ K ≤ 10

• 1 ≤ L i ≤ R i ≤ N

Sample Input 1 (standard input):

5 3 2

100 3 1 87 6

1 1

1 5

3 4

Sample Output 1 (standard output):

0

90

87

Note: Use C language, don’t use function./recursive/void.

The input is N,M,K not only N &M.

Answer 1

#include <stdio.h>

int main()
{
    //N, M and K value
    int N, M, K;
    //for loop iteration
    int i, j;
    //to store Li, Ri and sum
    int Li[100000], Ri[100000], sum[100000];
    //Array A
    int A[100000];
    
    //user input for N and M
    scanf("%d %d %d", &N, &M, &K);
    
    //user input for Array A
    for(i = 0; i < N; i++)
    {
        scanf("%d", &A[i]);
    }
    
    //user input for Li and Ri and calculate sum of them
    for(i = 0; i < M; i++)
    {
        sum[i] = 0;  //initially sum is 0
        //user input for Li and Ri
        scanf("%d %d", &Li[i], &Ri[i]);
        
        //execute till Li to Ri
        do{
            //if odd index then added to sum
            if(Li[i] % K == 0)
            {
                sum[i] = sum[i] + A[Li[i] - 1];
            }
            Li[i]++;
        }while(Li[i] <= Ri[i]);
    }
    
    //to print sum
    printf("\n");
    for(i =0; i < M; i++)
    {
        printf("%d\n", sum[i]);
    }

    return 0;
}

Please refer below screenshot of code for better understanding of indentation.

Sample output is also given in above screenshot.