Vijos 学姐的逛街计划

//Achen
#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<cstdio>
#include<vector>
#include<queue>
#include<ctime>
#include<cmath>
#define inf 1e18
const int N=10007; 
typedef long long LL;
using namespace std;
int n,k;
LL c[N];

template<typename T> void read(T &x) {
    char ch=getchar(); x=0; T f=1;
    while(ch!=‘-‘&&(ch<‘0‘||ch>‘9‘)) ch=getchar();
    if(ch==‘-‘) f=-1,ch=getchar();
    for(;ch>=‘0‘&&ch<=‘9‘;ch=getchar()) x=x*10+ch-‘0‘; x*=f;
}

struct edge {
    int u,v,nx;
    LL fl,cap,cost;
    edge(){}
    edge(int u,int v,LL fl,LL cap,LL cost,int nx):u(u),v(v),fl(fl),cap(cap),cost(cost),nx(nx){} 
}e[N]; 

int fir[N],ecnt=1;
void add(int u,int v,LL cap,LL cost) {
    e[++ecnt]=edge(u,v,0,cap,cost,fir[u]); fir[u]=ecnt;
    e[++ecnt]=edge(v,u,0,0,-cost,fir[v]); fir[v]=ecnt;
}

int vis[N],p[N];
LL dis[N];
queue<int>que;
int spfa(int s,int t) {
    for(int i=1;i<=n;i++) vis[i]=0,dis[i]=inf;
    que.push(s); dis[s]=0;
    while(!que.empty()) {
        int x=que.front();
        que.pop(); vis[x]=0;
        for(int i=fir[x];i;i=e[i].nx) 
        if(e[i].cap>e[i].fl) {
            int y=e[i].v;
            if(dis[y]>dis[x]+e[i].cost) {
                dis[y]=dis[x]+e[i].cost;
                p[y]=i; 
                if(!vis[y]) {
                    vis[y]=1;
                    que.push(y);
                }
            }
        }
    }
    return dis[t]!=inf;
}

LL calc(int s,int t) {
    LL fl=inf,res=0;
    for(int i=t;i!=s;i=e[p[i]].u) 
        fl=min(fl,e[p[i]].cap-e[p[i]].fl),
        res+=e[p[i]].cost;
    for(int i=t;i!=s;i=e[p[i]].u) 
        e[p[i]].fl+=fl,e[p[i]^1].fl-=fl;
    return fl*res;
} 

LL max_flow(int s,int t) {
    LL res=0;
    while(spfa(s,t)) 
        res+=calc(s,t);
    return res;
}

int main() {
    read(n); read(k);
    for(int i=1;i<=3*n;i++) read(c[i]);
    int s=2*n+3,t=s+1;
    add(s,2*n+1,k,0);
    add(2*n+2,t,k,0);
    for(int i=1;i<=n;i++) {
        add(i,2*n+2,1,-c[i]);
        add(2*n+1,n+i,1,-c[2*n+i]);
        add(n+i,i,1,-c[n+i]);
    } 
    for(int i=2;i<=2*n;i++) add(i,i-1,k,0);
    add(1,2*n+2,k,0);
    add(2*n+1,2*n,k,0);
    n=t;
    LL ans=-max_flow(s,t);
    printf("%lld\n",ans);
    return 0;
}