11_Question.cpp

// Problem Statement

// An intelligence agency has received reports about some threats. The reports consist of numbers in a mysterious method. 
// There is a number “N” and another number “R”. Those numbers are studied thoroughly and it is concluded that all digits of
// the number ‘N’ are summed up and this action is performed ‘R’ number of times.
// The resultant is also a single digit that is yet to be deciphered. The task here is to find the single-digit sum of the 
// given number ‘N’ by repeating the action ‘R’ number of times.

// If the value of ‘R’ is 0, print the output as ‘0’.

// Example 1:

// Input :

// 99 -> Value of N

// 3  -> Value of R

// Output :

// 9  -> Possible ways to fill the cistern.

// Explanation:

// Here, the number N=99

// Sum of the digits N: 9+9 = 18
// Repeat step 2 ‘R’ times i.e. 3 tims  (9+9)+(9+9)+(9+9) = 18+18+18 =54
// Add digits of 54 as we need a single digit 5+4
// Hence , the output is 9.

// Example 2:

// Input :

// 1234   -> Value of N

// 2      -> Value of R

// Output :

// 2  -> Possible ways to fill the cistern

// Explanation:

// Here, the number N=1234

// Sum of the digits of N: 1+2+3+4 =10
// Repeat step 2 ‘R’ times i.e. 2 times  (1+2+3+4)+(1+2+3+4)= 10+10=20
// Add digits of 20 as we need a single digit. 2+0=2
// Hence, the output is 2.

// Constraints:

// 0<N<=1000

// 0<=R<=50

// The Input format for testing 

// The candidate has to write the code to accept 2 input(s)

// First input- Accept value for N (positive integer number)

// Second input: Accept value for R(Positive integer number)

// The output format for testing 

// The output should be a positive integer number or print the message (if any) given in the problem statement.
//  (Check the output in Example 1, Example 2).


#include<iostream>
using namespace std;

int SingleDigitSum(int N, int R){

    int sum = (N-1) % 9 + 1;
    int RTimes = sum * R;

    return (RTimes - 1) % 9 + 1;
}

int main(){
    int N;
    cin>>N;
    int R;
    cin>>R;
    cout<<SingleDigitSum(N,R);
    return 0;
}




// #include<bits/stdc++.h>
// using namespace std;

// int Sum(int N){
//     int sum = 0;
//     while (N){
//          sum += N % 10;
//          N /= 10;
//     }
//     return sum;
// }

// int SingleDigitSum(int N, int R){
//     if(R == 0) return 0;
//     int sumofN = Sum(N);
//     sumofN *= R;

//     while(floor(log10(sumofN)+1) > 1){
//         sumofN = Sum(sumofN);
//     }
//     return sumofN;  
// }

// int main(){
//     int N;
//     cin>>N;
//     int R;
//     cin>>R;

//     cout<<SingleDigitSum(N,R);
//     return 0;
// }