HDU 5294 .Tricks Device（多校第七题）

最短路加最小割
最小割等于最大流

#include <map>
#include <set>
#include <stack>
#include <queue>
#include <cmath>
#include <ctime>
#include <vector>
#include <cstdio>
#include <cctype>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>
using namespace std;
#define INF 0x3f3f3f3f
#define inf -0x3f3f3f3f
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define mem0(a) memset(a,0,sizeof(a))
#define mem1(a) memset(a,-1,sizeof(a))
#define mem(a, b) memset(a, b, sizeof(a))
typedef long long ll;
const int maxn=2010;
int dist[maxn];
int vis[maxn];
int changdu[maxn];
struct Edge{
    int from,to,cap,flow;
    Edge(int u,int v,int c,int f):from(u),to(v),cap(c),flow(f){}
};

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

    void init(int n){
        this->n=n;
        for(int i=1;i<=n;i++)
            G[i].clear();
        edges.clear();
    }

    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);
    }

    bool BFS(){
        mem0(vis);
        queue<int>Q;
        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()){
            mem0(cur);
            flow+=DFS(s,INF);
        }
        return flow;
    }
};

struct Edge1{
    int from,to,len;
    Edge1(int u,int v,int c):from(u),to(v),len(c){}
};
vector<int>G[maxn];
vector<Edge1>edge;

void add(int u,int v,int len){
    edge.push_back(Edge1(u,v,len));
    edge.push_back(Edge1(v,u,len));
    int m=edge.size();
    G[u].push_back(m-2);
    G[v].push_back(m-1);
}

void init(int n){
    for(int i=1;i<=n;i++)
        G[i].clear();
}

void spfa(int s){
    queue<int> Q;
    memset(dist,0x3f,sizeof(dist));
    dist[s]=0;
    mem0(vis);
    mem0(changdu);
    Q.push(s);
    vis[s]=1;
    changdu[s]=0;
    while(!Q.empty()){
        int x=Q.front();
        Q.pop();
        vis[x]=0;
        for(int i=0;i<G[x].size();i++){
            Edge1& e=edge[G[x][i]];
            if(dist[e.to]>dist[x]+e.len){
                dist[e.to]=dist[x]+e.len;
                changdu[e.to]=changdu[x]+1;
                if(!vis[e.to]){
                    vis[e.to]=1;
                    Q.push(e.to);
                }
            }
            if(dist[e.to]==dist[x]+e.len){
                changdu[e.to]=min(changdu[e.to],changdu[x]+1);
                if(!vis[e.to]){
                    vis[e.to]=1;
                    Q.push(e.to);
                }
            }
        }
    }
    return ;
}
Dinic ZYC;

int main(){
    int n,m;
    while(scanf("%d%d",&n,&m)!=EOF){
        int u,v,len,cost;
        init(n);
        for(int i=0;i<m;i++){
            scanf("%d%d%d",&u,&v,&len);
            add(u,v,len);
        }
        spfa(1);
        ZYC.init(n);
        for(int i=1;i<=n;i++)
            for(int j=0;j<G[i].size();j++){
                Edge1& e=edge[G[i][j]];
                if(dist[i]+e.len==dist[e.to]){
                    ZYC.AddEdge(i,e.to,1);
                }
            }
        //cout<<"PPPPP"<<changdu[n]<<endl;
        printf("%d %d\n",ZYC.Maxflow(1,n),m-changdu[n]);
    }
    return 0;
}