Linear Solution of Joseph Ring

Reference: https://www.luogu.com.cn/problem/P8671
Reference: https://zhuanlan.zhihu.com/p/121159246
Reference: https://blog.csdn.net/doge__/article/details/82429348

#include <bits/stdc++.h>
using namespace std;
int n,k,s;
int main(){
    
    
  cin>>n>>k;
  for(int i=2;i<=n;i++){
    
    
    s=(s+k)%i;
  }
  cout<<s+1<<endl;
  return 0;
}