POJ1861

来源：互联网发布：域名备案买什么服务器编辑：程序博客网时间：2024/06/06 01:42
#include<cstdio>#include<vector>#include<cstring>#include<algorithm>using namespace std;const int maxn=1000+10;const int maxm=15000+10;struct Edge{    int u,v,dist;    Edge(){}    Edge(int u,int v,int d):u(u),v(v),dist(d){}    bool operator<(const Edge &rhs)const    {        return dist < rhs.dist;    }};struct Kruskal{    int n,m;    Edge edges[maxm];    int fa[maxn];    vector<int> bag;    int findset(int x){ return fa[x]==-1? x:fa[x]=findset(fa[x]); }    void init(int n)    {        this->n=n;        m=0;        bag.clear();        memset(fa,-1,sizeof(fa));    }    void AddEdge(int u,int v,int dist)    {        edges[m++]=Edge(u,v,dist);    }    int kruskal()    {        int edge_max;        int sum=0;        int cnt=0;        sort(edges,edges+m);        for(int i=0;i<m;i++)        {            int u=edges[i].u, v=edges[i].v;            if(findset(u) != findset(v))            {                bag.push_back(i);                edge_max=edges[i].dist;                sum +=edges[i].dist;                fa[findset(u)] = findset(v);                if(++cnt>=n-1) break;            }        }        if(cnt<n-1) return -1;        return edge_max;    }}KK;int n,m;int main(){    int cnt=0;    scanf("%d%d",&n,&m);    int u,v,d;    KK.init(n);    for(int i=0;i<m;i++){        scanf("%d%d%d",&u,&v,&d);        KK.AddEdge(u,v,d);    }    int edge_max=KK.kruskal();    printf("%d\n%d\n",edge_max,n-1);    for(int i=0;i<n-1;i++){        int num=KK.bag[i];        int a=KK.edges[num].u,b=KK.edges[num].v;        printf("%d %d\n",a,b);    }    return 0;}
0 0