C++ Code to Count Children Who Will Get Ball After Each Throw

Suppose we have a number n. Few kids are standing on a circle. They are numbered from 1 to n, they are in clockwise order and the child number 1 is holding the ball. First the child number 1 throws the ball to the next one clockwise, Then the child number 2 throws the ball to the next but one child, (to the child number 4), then the fourth child throws the ball to the child number 7 and so on. When a ball is thrown it may pass the beginning of the circle. Not all the children get the ball during the game. If a child doesn't get the ball, We have to find the numbers of the children who will get the ball after each throw.

So, if the input is like n = 10, then the output will be [2, 4, 7, 1, 6, 2, 9, 7, 6].

Steps

To solve this, we will follow these steps −

p := 1
for initialize i := 1, when i < n, update (increase i by 1), do:
   p := p + i
   p := p mod n
   if not p is non-zero, then:
      p := n
   print p

Example

Let us see the following implementation to get better understanding −

#include <bits/stdc++.h>
using namespace std;
void solve(int n){
   int p = 1;
   for (int i = 1; i < n; i++){
      p += i;
      p %= n;
      if (!p)
         p = n;
      printf("%d, ", p);
   }
}
int main(){
   int n = 10;
   solve(n);
}

Input

10

Output

2, 4, 7, 1, 6, 2, 9, 7, 6,