网络流板子（Dicnic）

int cnt,s,t,n,m;
int head[maxn],Next[maxn*20],to[maxn*20];
int flow[maxn*20],dep[maxn],cur[maxn],mp[405][405];
int dir[8][2]={1,2,1,-2,-1,2,-1,-2,-2,-1,-2,1,2,1,2,-1};
inline void add(int u,int v,int w){
    Next[cnt]=head[u];
    head[u]=cnt;
    to[cnt]=v;
    flow[cnt++]=w;

    Next[cnt]=head[v];
    head[v]=cnt;
    to[cnt]=u;
    flow[cnt++]=0;
}
int dfs(int u,int cost){
    if(u==t) return cost;
    for(int &i=cur[u];i!=-1;i=Next[i]){
        if(dep[to[i]]==dep[u]+1&&flow[i]>0){
           int dis=dfs(to[i],min(flow[i],cost));
            if(dis>0){
                flow[i]-=dis;
                flow[i^1]+=dis;
                return dis;
            }
        }
    }
    return 0;
}
int bfs(){
    queue<int> q;
    q.push(s);
    memset(dep,0,sizeof(dep));
    dep[s]=1;
    while(!q.empty()){
        int u=q.front();
        q.pop();
        for(int i=head[u];i!=-1;i=Next[i]){
            if(flow[i]>0&&dep[to[i]]==0){
                dep[to[i]]=dep[u]+1;
                q.push(to[i]);
            }
        }
    }
    if(dep[t]>0) return 1;
    return 0;
}
int dicnic(){
    int ans=0;
    while(bfs()){
        int cost;
        for(int i=0;i<=t+2;i++){
            cur[i]=head[i];
        }
        while(cost=dfs(s,inf))
            ans+=cost;
    }
    return ans;
}
void init(){
    memset(head,-1,sizeof(head));
    cnt=0;
}