没看出来哪错了啊

#include<iostream>
#include<queue>
#include<algorithm>
#include<cstring>
using namespace std;
int n,m;
bool flag[1001]={0};
queue<int> q;
int main()
{
    int i,j,num,sum=0;
    cin>>m>>n;
    for(i=1;i<=n;i++)
    {
        cin>>num;
        if(flag[num]==0)
        {
            if(q.size()<=m)
            {
                q.push(num);
                flag[num]=1;
            }
            else
            {
                flag[q.front()]=0;
                q.pop();
                q.push(num);
                flag[num]=1;
            }
            sum++;
        }
        else continue;
    }
    cout<<sum;
    return 0;
}