queue库好用！

#include<iostream>
#include<queue>

using namespace std;
int main()
{
    queue<int> q;
    int n; //n为报数总人数，m为报数号,1~m 
    cin >> n; 
    for(int i = 1;i<=n;i++)
    {
        q.push(i);
    }
    int count = 0;
    while(q.size() > 1)
    {
        count ++;
        int front = q.front();
        q.pop();
        if(count == 3)
            count = 0;
        else
            q.push(front);
    }
    cout << q.front() << endl;
    return 0;
}