https://vjudge.net/problem/HDU-6582

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<map>
#include<vector>
#include<string>
#include<cstring>
#include<queue>
using namespace std;
const int maxn=1e4+10;
const long long inf=1e16;
struct SimpleEdge
{
    int from,to;
    long long dis;
    SimpleEdge(int from,int to,long long dis)
    {
        this->from=from,this->to=to,this->dis=dis;
    }
};
struct Node
{
    int id;
    long long dis;
    Node(int id,long long dis)
    {
        this->id=id,this->dis=dis;
    }
    bool operator<(const Node &r)const
    {
        return this->dis>r.dis;
    }
};
struct Edge
{
    int from,to;
    long long cap,flow;
    Edge(int fr,int to,long long ca,long long fl)
    {
        this->from=fr,this->to=to,this->cap=ca,this->flow=fl;
    }
};
struct Dinic
{
    vector<int> G[maxn];
    vector<Edge> edges;
    bool vis[maxn];
    int n,s,t,cur[maxn];
    long long d[maxn];
    void init(int s,int t,int n)
    {
        this->s=s,this->t=t;
        this->n=n;
        for(int i=1;i<=n;i++) G[i].clear();
        edges.clear();
    }
    void AddEdge(int from,int to,long long cap)
    {
        edges.push_back(Edge(from,to,cap,0));
        edges.push_back(Edge(to,from,0,0));
        G[from].push_back(edges.size()-2);
        G[to].push_back(edges.size()-1);
    }
    bool bfs()
    {
        memset(vis,0,sizeof(vis));
        queue<int> Q;
        Q.push(s);
        d[s]=0,vis[s]=true;
        while(!Q.empty())
        {
            int now=Q.front();Q.pop();
            for(int i=0,_size=G[now].size();i<_size;i++)
            {
                Edge &e=edges[G[now][i]];
                if(!vis[e.to]&&e.cap>e.flow)
                {
                    vis[e.to]=true;
                    d[e.to]=d[now]+1;
                    Q.push(e.to);
                }
            }
        }
        return vis[t];
    }
    int dfs(int x,long long a)
    {
        if(x==t||a==0) return a;
        long long flow=0,f;
        for(int &i=cur[x],_size=G[x].size();i<_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) break;
            }
        }
        return flow;
    }
    long long MaxFlow()
    {
        long long ans=0;
        while(bfs())
        {
            memset(cur,0,sizeof(cur));
            ans+=dfs(s,inf);
        }
        return ans;
    }
}maxflow;
vector<int> G[maxn];
vector<SimpleEdge> edges;
int n,m,from,to;
long long dis,d[maxn];
bool done[maxn];
void init_all()
{
    edges.clear();
    for(int i=1;i<=n;i++) G[i].clear();
    maxflow.init(1,n,n);
}
int main()
{
    // freopen("in.txt","r",stdin);
    int T;scanf("%d",&T);while(T--)
    {
        scanf("%d %d",&n,&m);init_all();
        while(m--)
        {
            scanf("%d %d %lld",&from,&to,&dis);
            edges.push_back(SimpleEdge(from,to,dis));
            G[from].push_back(edges.size()-1);
        }
        for(int i=1;i<=n;i++) d[i]=inf;
        memset(done,0,sizeof(done));
        d[1]=0;priority_queue<Node> nodes;
        nodes.push(Node(1,0));
        while(!nodes.empty())
        {
            int now=nodes.top().id;
            nodes.pop();
            if(done[now]) continue;
            done[now]=true;
            for(int x=0,_size=G[now].size();x<_size;x++)
            {
                SimpleEdge &e=edges[G[now][x]];
                if(e.dis+d[now]<d[e.to])
                {
                    d[e.to]=e.dis+d[now];
                    nodes.push(Node(e.to,d[e.to]));
                }
            }
        }
        for(int i=1;i<=n;i++)
        {
            for(int x=0,_size=G[i].size();x<_size;x++)
            {
                SimpleEdge &e=edges[G[i][x]];
                if(d[e.to]==e.dis+d[e.from])
                {
                    maxflow.AddEdge(e.from,e.to,e.dis);
                }
            }
        }
        printf("%lld\n",maxflow.MaxFlow());
    }
    return 0;
}