【Luogu】P2604网络扩容（费用流乱搞）

　　题目链接

　　这题比较水，就是乱改改费用流模板。判断一下已经满流的边和没有满流的边，然后再改改最大流模板，然后把它们拼起来就是了。

　　话说这题第一遍90，然后撕烤一会发现自己yy的spfa扩容方式不允许反悔。然后改了一个貌似没什么用的地方，结果A了……

　　但是改的那个地方貌似是真的没什么用啊……

#include<cstdio>
#include<cstdlib>
#include<cctype>
#include<algorithm>
#include<cstring>
#include<queue>
#define maxn 2000
#define maxm 10000
using namespace std;

inline long long read(){
    long long num=0,f=1;
    char ch=getchar();
    while(!isdigit(ch)){
        if(ch=='-')    f=-1;
        ch=getchar();
    }
    while(isdigit(ch)){
        num=num*10+ch-'0';
        ch=getchar();
    }
    return num*f;
}

inline int count(int i){    return i&1?i+1:i-1;    }

struct Edge{
    int from,next,to,dis,val,flow;
}edge[maxm*2];
int head[maxn],num;
inline void addedge(int from,int to,int dis,int val){
    edge[++num]=(Edge){from,head[from],to,dis,val,0};
    head[from]=num;
}
inline void add(int from,int to,int dis,int val){
    addedge(from,to,dis,val);
    addedge(to,from,-dis,0);
}

int dfn[maxn];
bool vis[maxn];
int Start,End;
int list[maxn];

bool bfs(){
    memset(vis,0,sizeof(vis));
    dfn[Start]=1;    vis[Start]=1;
    queue<int>q;    q.push(Start);
    while(!q.empty()){
        int from=q.front();q.pop();
        for(int i=head[from];i;i=edge[i].next){
            int to=edge[i].to;
            if(edge[i].val==edge[i].flow||vis[to])    continue;
            vis[to]=1;
            dfn[to]=dfn[from]+1;    q.push(to);
        }
    }
    return vis[End];
}

int dfs(int x,int val){
    if(x==End||val==0)    return val;
    int flow=0;    vis[x]=1;
    for(int &i=list[x];i;i=edge[i].next){
        int to=edge[i].to;
        if(edge[i].val==edge[i].flow||vis[to]||dfn[to]!=dfn[x]+1)    continue;
        int now=dfs(to,min(val,edge[i].val-edge[i].flow));
        edge[i].flow+=now;    edge[count(i)].flow-=now;    val-=now;    flow+=now;
        if(val<=0)    break;
    }
    if(flow!=val)    dfn[x]=-1;
    return flow;
}

int dis[maxn];
int pre[maxn];

int spfa(){
    memset(dis,127/3,sizeof(dis));    dis[Start]=0;
    memset(vis,0,sizeof(vis));
    queue<int>q;    q.push(Start);
    while(!q.empty()){
        
        int from=q.front();    q.pop();    vis[from]=0;
        for(int i=head[from];i;i=edge[i].next){
            int to=edge[i].to;
            if(edge[i].val>edge[i].flow){
                if(dis[to]<=dis[from])    continue;
                dis[to]=dis[from];
            }
            else{
                if(edge[i].dis<0)    continue;
                if(dis[to]<=dis[from]+edge[i].dis)    continue;
                dis[to]=dis[from]+edge[i].dis;
            }
            pre[to]=i;
            if(vis[to])    continue;
            vis[to]=1;    q.push(to);
        }
    }
    int now=End;
    while(now!=Start&&now){
        int ret=pre[now];
        if(edge[ret].val==edge[ret].flow)    edge[ret].val++;
        edge[ret].flow++;    edge[count(ret)].flow--;
        now=edge[ret].from;
    }
    return dis[End];
}

int main(){
    int n=read(),m=read(),e=read();End=n;Start=1;
    for(int i=1;i<=m;++i){
        int a=read(),b=read(),c=read(),d=read();
        add(a,b,d,c);
    }
    int ans=0;
    while(bfs()){
        memset(vis,0,sizeof(vis));
        for(int i=1;i<=n;++i)    list[i]=head[i];
        int now=dfs(Start,0x7fffffff);
        if(!now)    break;
        ans+=now;
    }
    printf("%d",ans);
    long long now=0;
    for(int i=1;i<=e;++i)
        now+=spfa();
    printf(" %lld",now);
    return 0;
}