LibreOJ #507. 「LibreOJ NOI Round #1」接竹竿

/*
    LibreOJ #507. 「LibreOJ NOI Round #1」接竹竿
    
    dp
    记录一下前驱就好了
    再随便用前缀和优化一下
    O(N)

*/
#include <iostream>
#include <cstdio>

const int BUF = 100000010;
char Buf[BUF], *buf = Buf;

inline long long max (long long a, long long b)
{
    return a > b ? a : b;
}

void read (int &now)
{
    for (now = 0; !isdigit (*buf); ++ buf);
    for (; isdigit (*buf); now = now * 10 + *buf - ‘0‘, ++ buf);
}

#define Max 1000020
int N, K;
long long sum[Max];

int to[Max];
int last_kind[Max * 100];

long long dp[Max];

int main (int argc, char *argv[])
{
    fread (buf, 1, BUF, stdin);
    read (N);
    read (K);
    
    register int i;
    int x;
    for (i = 1; i <= N; ++ i)
    {
        read (x);
        to[i] = last_kind[x];
        last_kind[x] = i;
    }

    for (i = 1; i <= N; ++ i)
    {
        read (x);
        sum[i] = sum[i - 1] + x; 
    }

    register int res;
    for (i = 1; i <= N; ++ i)
    {
        dp[i] = dp[i - 1];
        if (to[i])
            dp[i] = max (dp[i], max (dp[to[i]] + sum[i] - sum[to[i]], dp[to[i] - 1] + sum[i] - sum[to[i] - 1]));
    }  

    printf ("%lld", dp[N]);
    return 0;
}