2821: 开关灯

解题思路:

注意事项:

参考代码:

#include<bits/stdc++.h>

typedef long long ll;

const int N=1e5;

ll a[N];

using namespace std;

int main()

{

    ll n,m;

    cin>>n>>m;

    for(int i=1; i<=m; i++)

    {

        for(int j=1; j<=n; j++)

        {

            if(j%i==0)

            {

                if(a[j]==0)

                {

                    a[j]=1;

                }

                else

                {

                    a[j]=0;

                }

            }

        }

    }

    ll b=1;

    for(int i=1; i<=n; i++)

    {

        if(a[i]==1)

        {

            if(b==1)

            {

                cout<<i;

                b=0;

            }

            else

            {

                cout<<','<<i;

            }

        }

    }

    return 0;

}