bzoj 2055 80人环游地球(上下界费用流)

/**************************************************************
    Problem: 2055
    User: Clare
    Language: C++
    Result: Accepted
    Time:560 ms
    Memory:2140 kb
****************************************************************/
 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
using namespace std;
 
#define N 210
#define INF 0x3f3f3f3f
 
int n,m,SS,S,T;
struct Edge{
    int next,value,to,cost,from;
}edge[N*N];
int head[N],tot=1;
int pre[N],dis[N],in[N];
long long Ans;
bool exist[N];
queue Q;
 
inline int read()
{
    int x=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
    while(ch<='9'&&ch>='0'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}
 
void Addedge(int u,int v,int w,int c)
{
    tot++;edge[tot].next=head[u];edge[tot].from=u;edge[tot].to=v;
    edge[tot].value=w;edge[tot].cost=c;head[u]=tot;
    tot++;edge[tot].next=head[v];edge[tot].from=v;edge[tot].to=u;
    edge[tot].value=0;edge[tot].cost=-c;head[v]=tot;
}
 
bool SPFA()
{
    memset(dis,INF,sizeof(dis));
    memset(exist,0,sizeof(exist));
    dis[S]=0;exist[S]=true;
    Q.push(S);
    while(!Q.empty())
    {
        int now=Q.front();Q.pop();
        exist[now]=false;
        for(int i=head[now];i;i=edge[i].next)
        {
            int v=edge[i].to;
            if(edge[i].value>0&&dis[v]>dis[now]+edge[i].cost)
            {
                dis[v]=dis[now]+edge[i].cost;
                pre[v]=i;
                if(!exist[v])
                {
                    exist[v]=true;
                    Q.push(v);
                }
            }
        }
    }
    if(dis[T]!=INF)
        return true;
    else return false;
}
 
void DFS()
{
    int qwer=INF;
    for(int i=pre[T];i;i=pre[edge[i].from])
        qwer=min(qwer,edge[i].value);
    for(int i=pre[T];i;i=pre[edge[i].from])
    {
        edge[i].value-=qwer;
        edge[i^1].value+=qwer;
        Ans+=(long long)qwer*edge[i].cost;
    }
}
 
int main()
{
    n=read();m=read();
    S=0;SS=2*n+1;T=2*n+2;
    for(int i=1;i<=n;i++)
    {
        int x=read();
        Addedge(i,i+n,0,0);
        in[i]-=x;in[i+n]+=x;
    }
    Addedge(S,SS,m,0);
    for(int i=1;i<=n;i++)
        Addedge(SS,i,INF,0);
    for(int i=1;i<=n;i++)
    {
        for(int j=i+1;j<=n;j++)
        {
            int x=read();
            if(x==-1)
                continue;
            Addedge(i+n,j,INF,x);
        }
    }
    for(int i=1;i<=2*n;i++)
    {
        if(in[i]>0)
            Addedge(S,i,in[i],0);
        else Addedge(i,T,-in[i],0);
    }
    while(SPFA())
        DFS();
    cout<