Manthan, Codefest 19 (open for everyone, rated, Div. 1 + Div. 2)B（SET）

#define HAVE_STRUCT_TIMESPEC
#include<bits/stdc++.h>
using namespace std;
int a[2007];
set<int>s;
int main(){
int n;
cin>>n;
int iend=n+1;
for(int i=1;i<=n;++i)
cin>>a[i];
while(iend>1&&!s.count(a[iend-1]))
s.insert(a[--iend]);
int ans=9999;
for(int i=1;iend<=n+1;++iend){
while(i<iend&&!s.count(a[i]))
s.insert(a[i++]);
ans=min(ans,iend-i);
s.erase(a[iend]);
}
cout<<ans;
return 0;
}