Codeforces Gym 101190 NEERC 16 .D Delight for a Cat （上下界的费用流）

#include<bits/stdc++.h>
#define ll long long
#define maxn 1010
#define inf 1<<30
using namespace std;
int To[maxn<<2],Laxt[maxn],Next[maxn<<2],cap[maxn<<2],cost[maxn<<2],tag[maxn];
int N,S,T,cnt=1;  ll dis[maxn],ans;//费用
bool inq[maxn],vis[maxn];
deque<int>q;
void add(int u,int v,int c,int cc)
{ Next[++cnt]=Laxt[u];Laxt[u]=cnt;To[cnt]=v;cap[cnt]=c;cost[cnt]=cc; }
bool spfa()
{
    memset(inq,0,sizeof(inq));
    for(int i=0;i<=T;i++) dis[i]=1LL<<40;
    inq[T]=1; dis[T]=0; q.push_back(T);
    while(!q.empty())
    {    
        int u=q.front(); q.pop_front();
        inq[u]=0;
        for(int i=Laxt[u];i;i=Next[i])
        {
            int v=To[i];
            if(cap[i^1]&&dis[v]>dis[u]-cost[i])
            {
                dis[v]=dis[u]-cost[i];
                if(!inq[u]){
                    inq[v]=1;
                    if(q.empty()||dis[v]>dis[q.front()]) q.push_back(v);
                    else q.push_front(v);
                }
            }
        }
    }
    return dis[S]<(1LL<<40);
}
int dfs(int u,int flow)
{
    vis[u]=1;
    if(u==T||flow==0) return flow;
    int tmp,delta=0;
    for(int i=Laxt[u];i;i=Next[i])
    {
        int v=To[i];
        if((!vis[v])&&cap[i]&&dis[v]==dis[u]-cost[i])
        {
            tmp=dfs(v,min(cap[i],flow-delta));
            delta+=tmp; cap[i]-=tmp; cap[i^1]+=tmp;
        }
    }
    return delta;
}
int s[maxn],e[maxn];
int main()
{
    int N,K,mn,mx,ans=0,i;
    scanf("%d%d%d%d",&N,&K,&mx,&mn);
    for(i=1;i<=N;i++) scanf("%d",&s[i]),ans+=s[i];
    for(i=1;i<=N;i++) scanf("%d",&e[i]),e[i]-=s[i];
    mx=K-mx; S=0; T=N+1;
    add(S,1,mx,0); add(1,S,0,0);
    for(i=1;i<=N;i++) add(i,i+1,mx-mn,0),add(i+1,i,0,0);
    for(i=1;i<=N;i++) add(i,i+K>N?T:i+K,1,-e[i]),tag[i]=cnt,add(i+K>N?T:i+K,i,0,e[i]);
    while(spfa()){
        vis[T]=1;
        while(vis[T]){
            memset(vis,0,sizeof(vis));
            int tmp=dfs(S,inf);
            ans-=(ll)tmp*dis[S];
        }
    }
    printf("%I64d\n",ans);
    for(i=1;i<=N;i++) 
       if(cap[tag[i]]) putchar(‘S‘);
       else putchar(‘E‘);
    return 0;
}