bzoj3550: [ONTAK2010]Vacation&&1283: 序列

#include<bits/stdc++.h>
#define rep(i,l,r) for(int i=l;i<=r;++i)
using namespace std;
const int N=10240,inf=214748364;
struct Edge{
    int to,next,from,c,w;
}e[1000000];
int head[N],tot=1,ans,dis[N],from[N],m,K,n,T,x;
bool used[N];
inline void ins(int u,int v,int w,int cost) {
     e[++tot].to=v; e[tot].next=head[u]; head[u]=tot; e[tot].w=w; e[tot].c=cost; e[tot].from=u;
}
inline bool spfa() {
     queue<int> q; rep(i,0,T) dis[i]=-1,from[i]=0,used[i]=0; dis[0]=1; q.push(0); used[0]=1;  
     while(!q.empty()) {
          int x=q.front(); q.pop();
          used[x]=0;
          for(int k=head[x];k;k=e[k].next) 
           if(e[k].w>0&&dis[x]+e[k].c>dis[e[k].to]){
                  dis[e[k].to]=dis[x]+e[k].c; from[e[k].to]=k;
                  if(!used[e[k].to]) {
                        used[e[k].to]=1; q.push(e[k].to);
                  }
            }
     }
     return dis[T]!=-1;
}
inline void run(){
     int x=inf;
     for(int k=from[T];k;k=from[e[k].from]) x=min(x,e[k].w);
     for(int k=from[T];k;k=from[e[k].from]) {
          e[k].w-=x; e[k^1].w+=x; ans+=e[k].c*x;
     }
}
inline void insert(int u,int v,int w,int c){
    ins(u,v,w,c); ins(v,u,0,-c);
}
int main(){
    scanf("%d%d",&m,&K); n=m*3;
    T=n+1;
    rep(i,1,n) {
        scanf("%d",&x);
        insert(i-1,i,K,0);
        if(i+m<=n) insert(i,i+m,1,x);else insert(i,T,1,x);
    }
    insert(n,T,K,0);
    while(spfa()) run();
    printf("%d\n",ans);
}