Dinic 贴个板子

#include<iostream>
#include<algorithm>
#include<cstring>
#include<queue>
using namespace std;
struct node
{
    int x;
    int num;
};
const int inf = 99999999;
int u[415],v[415],w[415],r[415];
int first[415],Next[415];
int num[415];
bool vis[415];
int n,m;
bool bfs(int s,int t)
{
    queue<node>q;
    memset(vis,0,sizeof(vis));
    q.push(node{s,1});
    node cur;vis[s]=true;
    while(!q.empty()){
        cur=q.front();q.pop();
        int k=first[cur.x];
        num[cur.x]=cur.num;//记录每一点的层数
        while(k!=-1){
            if(!vis[v[k]]&&w[k]>0){
                vis[v[k]]=true;
                q.push(node{v[k],cur.num+1});
            }
            k=Next[k];
        }
    }
    if(num[t]){return true;}
    else return false;
}

int dfs(int s,int t,int f)
{
    if(s==t){return f;}
    int k=first[s];
    vis[s]=true;
    int d;
    while(k!=-1){
        if(!vis[v[k]]&&w[k]>0&&num[u[k]]==num[v[k]]-1){
            int d=dfs(v[k],t,min(f,w[k]));
            w[k]-=d;
            w[r[k]]+=d;
            if(d!=0){return d;}
        }
        k=Next[k];
    }
    return 0;
}

int dinic(int s,int t)
{
    memset(num,0,sizeof(num));
    int ans=0;
    while(bfs(s,t)){
        int d;
        memset(vis,0,sizeof(vis));
        while(d=dfs(s,t,inf)){
            ans+=d;
            memset(vis,0,sizeof(vis));
        }
        memset(num,0,sizeof(num));
    }
    return ans;
}

int main()
{
    while(cin>>m>>n){
        fill(first,first+410,-1);
        for(int i=0;i<2*m;i++){
            cin>>u[i]>>v[i]>>w[i];
            r[i]=i+1;//记录反向边的编号
            Next[i]=first[u[i]];
            first[u[i]]=i;
            i++;
            u[i]=v[i-1];
            v[i]=u[i-1];
            w[i]=0;
            r[i]=i-1;
            Next[i]=first[u[i]];
            first[u[i]]=i;
        }
        cout<<dinic(1,n)<<endl;
    }
}