80分求助QWQ

#include<bits/stdc++.h>
using namespace std;
int k,a[5],sub1,sub2,sub3;
bool n;
int main(){
	cin>>k;
	for(int i=10000;i<=30000;i++){
		sub1=i/100;
		sub2=i%10000/10;
		sub3=i%1000;
		if((sub1%k==0)&&(sub2%k==0)&&(sub3%k==0)){
			n=1;
			cout<<i<<endl;
		}
	}
	if(n!=1){
		cout<<"No";
	}
	return 0;
}