HDU 3549 Flow Problem（网络流模板题）

记录一下模板

#include <vector>
#include <cstring>
#include <algorithm>
#include <cstdio>
#include <queue>
using namespace std;

#define maxn 1100
#define INF 0x7f7f7f7f
struct Edge {
    int from,to,cap,flow;
};

struct  Dinic {
    int n,m,s,t;
    vector<Edge>edges;
    vector<int>G[maxn];
    bool vis[maxn];
    int d[maxn];
    int cur[maxn];

    void addEdge(int from,int to,int cap) {
    edges.push_back((Edge) {from,to,cap,0});
    edges.push_back((Edge) {to,from,0,0});
    m=edges.size();
    G[from].push_back(m-2);
    G[to].push_back(m-1);
    }

    void init(){
      edges.clear();
      for(int i=1;i<=maxn;i++) G[i].clear();
    }
    bool Bfs() {
        memset(vis,0,sizeof(vis));
        queue<int>Q;
        while(!Q.empty()) Q.pop();
        Q.push(s);
        d[s]=0;
        vis[s] = 1;
        while(!Q.empty()) {
            int x = Q.front();
            Q.pop();
            for(int i=0; i<G[x].size(); i++) {
                Edge& e = edges[G[x][i]];
                if(!vis[e.to]&&e.cap>e.flow) {
                    vis[e.to] = 1;
                    d[e.to] = d[x]+1;
                    Q.push(e.to);
                }
            }
        }
        return vis[t];
    }

    int dfs(int x,int a) {
        if(x==t||a==0) return a;
        int flow = 0,f;
        for(int &i=cur[x]; i<G[x].size(); i++) {
            Edge& e  = edges[G[x][i]];
            if(d[x]+1==d[e.to]&&(f=dfs(e.to,min(a,e.cap-e.flow)))>0) {
                e.flow += f;
                edges[G[x][i]^1].flow -= f;
                flow += f;
                a -= f;
                if(a==0) break;
            }
        }
        return flow;
    }

    int maxflow(int s,int t) {

        this->s=s;
        this->t=t;
        int flow  = 0;
        while(Bfs()) {
            memset(cur,0,sizeof(cur));
            flow+=dfs(s,INF);
        }
        return flow;
    }
};

int main(){
    int T;
    int n,k;
    Dinic slove;

    while(scanf("%d",&T)==1){
    int cas=0;
    while(T--){
        scanf("%d%d",&n,&k);
        slove.init();
        while(k--){
            int x,y,z;
            scanf("%d%d%d",&x,&y,&z);
            slove.addEdge(x,y,z);
        }
        printf("Case %d: %d\n",++cas,slove.maxflow(1,n));
    }
    }
}

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