Josephus Problem I

Solution

#include <bits/stdc++.h>
using namespace std;
//author: von_Braun
#define ll long long
#define lli long long int
#define pb push_back
#define rep(var, start, num) for(ulli var = start; var <start + num; var++)
#define all(x) x.begin(), x.end()
#define ulli unsigned long long int
#define ull unsigned long long
bool sortbysec(const pair<ll,ll> &a,const pair<ll,ll> &b) { return (a.second < b.second); }

void solve() {
    int n;
    cin>>n;
    set<int> S;
    rep(i,1,n) {S.insert(i);}
    int k=2;
    auto it = S.find(k);
    while(!S.empty()) {
        cout<<*it<<" ";
        int t = *it;
        it++;
        S.erase(t);
        if (S.size()==0) {break;}
        if (it==S.end()) {it = S.begin();}
        rep(j,0,k-1) {
        it++;
        if (it==S.end()) {it = S.begin();}
        }
    }     
}

int main() {
    //add quotes incase input output file
    //freopen(input.txt,r,stdin);
    //freopen(output.txt,w,stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int tc = 1;
    // cin >> tc;
    for (int t = 1; t <= tc; t++) {
        solve();
    }
}