这道题 unknown errow 可是我绑定了 uva 呀！！！

#include<iostream>
#include<map>
using namespace std;
map< int, int > s;
int t, n, ans, end, a; 
int main()
{
	cin >> t;
	while( t-- )
	{
		s.clear();
		cin >> n;
		end = 0, ans = 0;
		for( int i = 1; i <= n; i++ )
		{
			cin >> a;
			end = max( end, s[ a ] );
			//cout << s[ a ] << endl;
			ans = max( ans, i - end );
			s[ a ] = i;
		}
		cout << ans << endl;
	}
	return 0;
}