自己懒得写网络流用的，你也可以拿去用：
普通最大流：

struct FLOW{
    int flow[N],nex[N],first[N],v[N],dep[N],q[N],no[N],num=1,aim,fromt[N];
    void add(int from,int to,int val){nex[++num]=first[from];fromt[num]=from;first[from]=num;v[num]=to;flow[num]=val;}
    bool bfs(int s,int t){
        for(int i=s;i<=t;i++) dep[i]=0,q[i]=0;
        q[1]=s;dep[s]=1;no[s]=first[s];
        int head=0,tail=1;
        while(head!=tail){
            int u=q[++head];
            for(int i=first[u];i;i=nex[i]){int to=v[i];if(flow[i] && !dep[to]){no[to]=first[to];dep[to] = dep[u] + 1;q[++tail] = to;}}
        }
        return dep[t]!=0;
    }
    int dfs(int now,int fl){
        if(now==aim) return fl;
        int f=0;
        for(int i=no[now];i&&fl;i=nex[i]){
            no[now]=i;int to=v[i];
            if(flow[i] && dep[to] == dep[now]+1){int x=dfs(to,min(fl,flow[i]));flow[i]-=x;flow[i^1]+=x;fl-=x;f+=x; }
        }
        if(!f) dep[now]=-2;return f;
    }
    int mxflow(int s,int t){
        aim=t;int ret=0;
        while(bfs(s,t)) ret+=dfs(s,1<<30);
        return ret;
    }
}G;

最大费用最大流：

struct FLOW{
    int num=1,nex[N],first[N],v[N],flow[N],cost[N],dis[N],inf[N],last[N],vis[N],q[N];
    int pre[N],mincost,fromt[N],vib[N];
    void add(int from,int to,int val,int c){nex[++num]=first[from];fromt[num]=from;first[from]=num;v[num]=to;flow[num]=val;cost[num]=c;}
    bool spfa(int s,int t){
        memset(dis,0xcf,sizeof(dis));memset(vis,0,sizeof(vis));memset(inf,0x7f,sizeof(inf));
        q[1]=s;vis[s]=1;dis[s]=0;pre[t]=-1;int l=0,r=1;
        while(l!=r){int u=q[++l];vis[u]=0;for(int i=first[u];i;i=nex[i]){int to=v[i];if(flow[i] && dis[to]<dis[u]+cost[i]){dis[to]=dis[u]+cost[i];pre[to]=u;last[to]=i;inf[to]=min(inf[u],flow[i]);if(!vis[to]){vis[to]=1;q[++r]=to;}}}}
        return pre[t]!=-1;
    }
    void EK(int s,int t){
        while(spfa(s,t)){
            int now=t;mincost+=inf[t]*dis[t];
            while(now!=s){flow[last[now]]-=inf[t];flow[last[now]^1]+=inf[t];now=pre[now];}
        }
    }
}G,T;

最小费用最大流：

struct FLOW{
    int num=1,nex[N],first[N],v[N],flow[N],cost[N],dis[N],inf[N],last[N],vis[N],q[N];
    int pre[N],mincost,fromt[N],vib[N];
    void add(int from,int to,int val,int c){nex[++num]=first[from];fromt[num]=from;first[from]=num;v[num]=to;flow[num]=val;cost[num]=c;}
    bool spfa(int s,int t){
        memset(dis,0x7f,sizeof(dis));memset(vis,0,sizeof(vis));memset(inf,0x7f,sizeof(inf));
        q[1]=s;vis[s]=1;dis[s]=0;pre[t]=-1;int l=0,r=1;
        while(l!=r){int u=q[++l];vis[u]=0;for(int i=first[u];i;i=nex[i]){int to=v[i];if(flow[i] && dis[to]>dis[u]+cost[i]){dis[to]=dis[u]+cost[i];pre[to]=u;last[to]=i;inf[to]=min(inf[u],flow[i]);if(!vis[to]){vis[to]=1;q[++r]=to;}}}}
        return pre[t]!=-1;
    }
    void EK(int s,int t){
        while(spfa(s,t)){
            int now=t;mincost+=inf[t]*dis[t];
            while(now!=s){flow[last[now]]-=inf[t];flow[last[now]^1]+=inf[t];now=pre[now];}
        }
    }
}G,T;