BZOJ4873 寿司餐厅

#include<bits/stdc++.h>
using namespace std;
const int N=105;
const int M=2e5;
int l=1,pre[M],other[M],last[M],cap[M],SUM,n,m,maxa;
int idw[N][N],S,T,ida[N*10],a[N],w[N][N],d[M],tot;
void add(int x,int y,int w)
{
    ++l;pre[l]=last[x];last[x]=l;
    other[l]=y;cap[l]=w;
    ++l;pre[l]=last[y];last[y]=l;
    other[l]=x;cap[l]=0;
}
void work(int x,int w)
{
    if(w<0) add(x,T,-w);
    else SUM+=w,add(S,x,w);
}
bool bfs()
{
    queue<int> q;
    memset(d,0,sizeof d);
    d[S]=1;q.push(S);
    while(!q.empty())
    {
        int u=q.front();q.pop();
        for(int p=last[u];p;p=pre[p])
        {
            int v=other[p];
            if(d[v]||!cap[p]) continue;
            d[v]=d[u]+1;
            q.push(v);
        }
    }
    if(d[T]) return 1;
    return 0;
}
int dfs(int x,int flow)
{
    if(x==T) return flow;
    if(!flow) return 0;
    int res=flow;
    for(int p=last[x];p;p=pre[p])
    {
        int y=other[p];
        if(cap[p]==0||d[y]!=d[x]+1) continue;
        int tmp=dfs(y,min(res,cap[p]));
        res-=tmp;
        cap[p]-=tmp;
        cap[p^1]+=tmp;
        if(tmp==0) d[y]=0;
        if(res==0) break;
    }
    return flow-res;
}
int dinic()
{
    int ans=0;
    while(bfs()) ans+=dfs(S,1e9);
    return ans;
}
int main()
{
    scanf("%d%d",&n,&m);
    for(int i=1;i<=n;++i) 
    scanf("%d",a+i),maxa=max(maxa,a[i]);
    for(int i=1;i<=n;++i)
        for(int j=i;j<=n;++j)
        scanf("%d",&w[i][j]),idw[i][j]=++tot;
    for(int i=1;i<=maxa;++i) ida[i]=++tot;
    S=tot+1;T=tot+2;
    for(int i=1;i<=n;++i)
        for(int j=i;j<=n;++j)
        if(i==j) work(idw[i][j],w[i][j]-a[i]);
        else 
        {
            work(idw[i][j],w[i][j]);
            add(idw[i][j],idw[i+1][j],1<<30);
            add(idw[i][j],idw[i][j-1],1<<30);
        }
    for(int i=1;i<=maxa;++i) work(ida[i],-m*i*i);
    for(int i=1;i<=n;++i) add(idw[i][i],ida[a[i]],1<<30);
    SUM-=dinic();
    cout<<SUM;
}