本文转载自  Fy1999  查看原文  2018-07-31  8    uva/uva/ 窗口/窗口/ set/set/ 思想/思想/ 滑动滑动           

#include <iostream>
#include <cstring>
#include <set>
#include <cstdio>
#include <algorithm>
#define N 1e7+10

using namespace std;
int read()
{
    int x=0,f=1;char c=getchar();
    while (c<'0'||c>'9') {if (c=='-') f=-1;c=getchar();}
    while (c>='0'&&c<='9') x=(x<<1)+(x<<3)+(c^48),c=getchar();
    return x*f;
}

int T,n,a[10000005];
int main()
{

    T=read();
    while(T--){
        n=read();
        for (int i=0;i<n;i++) a[i]=read();
        set<int>s;
        int l=0,r=0,ans=0;
        while(r<n){
            while(r<n&&!s.count(a[r])){
                s.insert(a[r++]);}
                ans=max(r-l,ans);
                s.erase(a[l]);
                l++;
        }
        cout<<ans<<endl;

    }


    return 0;
}