rt，赛时代码，A了，但为什么正确：

#include <cstring>
#include <string>
#include <stdio.h>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <stack>
#include <queue>
#include <limits.h>
#include <list>
#include <set>
#include <map>
#include <unordered_map>
#include <bitset>
#include <random>
using namespace std;
//#define min(a,b) ((a)>(b)?(b):(a))
//#define max(a,b) ((a)<(b)?(b):(a))
#define INF 0x3f3f3f3f
#define ll long long
#define sc scanf
#define pr printf
#define v1 first
#define v2 second
#define f(nm1,nm2,nm3) for(int nm1=nm2; nm1<= nm3; nm1++)
int t;
int n;
int a[200005];
int bf[200005];
int p[1000006];
ll dp[200005];
ll sum[200005];
void init()
{
    memset(p,0,sizeof(p));
    memset(bf,0,sizeof(bf));
    memset(dp,0,sizeof(dp));
    memset(sum,0,sizeof(sum));
    for(int i=1; i <= n; i++)
    {
        sum[i]=((a[i]==a[i-1])?a[i]:0)+sum[i-1];
        bf[i]=p[a[i]];
        p[a[i]]=i;
    }
}
ll getsum(int l,int r)
{
    if(l>r)
        return 0;
    return sum[r]-sum[l];
}
signed main()
{
    sc("%d",&t);
    while(t--)
    {
        sc("%d",&n);
        for(int i=1; i <= n; i++)
        {
            sc("%d",&a[i]);
        }
        init();
        for(int i=1; i <= n; i++)
        {
            dp[i]=dp[i-1]+((a[i]==a[i-1])?a[i-1]:0);
            if(bf[i])
            {
                if(bf[i]+1<i)
                {
                    dp[i]=max(dp[i],dp[bf[i]+1]+a[i]+getsum(bf[i]+1,i-1));
                }
                dp[i]=max(dp[i],dp[bf[i]]+a[i]+getsum(bf[i]+1,i-1));
                dp[i]=max(dp[i],dp[bf[i]-1]+a[i]+getsum(bf[i]+1,i-1));
            }
        }
        pr("%lld\n",dp[n]);
    }
    return 0;
}