Uva 10600

给出一个无向图，要求求出最小的两个生成树。
难么即是求出最小生成树和次小生成树。
次小生成树的求解过程是，先求解最小生成树，再在树上深搜，处理出maxcost[u][v]，表示树上u到v的路径上最大的边。然后枚举不在树上的边（i，j)，去替换树上的i到j最大的边，求最小即是次小生成树。

#include<bits/stdc++.h>
using namespace std;
#define debug puts("Infinity is awesome!")
#define mm(a,b) memset(a,b,sizeof(a))
#define LS (root<<1)
#define RS (root<<1|1)
#define LSON LS,l,mid
#define RSON RS,mid+1,r
#define LL long long
#define rep(a,b,c) for(int a=b;a<c;a++)
const int Inf=1e9+7;
const int maxn=105;
const int maxc=102;
const int maxe=1e6+5;
const int mod=1e9+7;
const int maxsize=maxn*maxn;

struct HeapNode{
    int u, d, eid;
    HeapNode(){}
    HeapNode(int a,int b,int c):u(a), d(b), eid(c){}
    bool operator <(const HeapNode &rhs)const{
        return d>rhs.d;
    }
};
struct Edge{
    int from, to, dist, next;
    Edge(){}
    Edge(int a,int b,int c,int d):from(a), to(b), dist(c), next(d){}
};
int n, m, ecnt;
Edge edges[maxe];
int head[maxn], vis[maxn];
int ontree[maxe];
void Init(){
    ecnt=0;
    mm(head,-1);
}
void Add_Edge(int u,int v,int w){
    edges[ecnt]=Edge(u,v,w,head[u]);
    head[u]=ecnt++;
}
int Prim(){
    mm(vis,0); mm(ontree,0);
    int cnt=0, sum=0;
    priority_queue<HeapNode> Q;
    Q.push(HeapNode(0,0,-1));
    while(cnt<n&&!Q.empty()){
        HeapNode x=Q.top(); Q.pop();
        if(vis[x.u]) continue;
        int u=x.u, eid=x.eid;
        vis[x.u]=1;
        if(eid!=-1){
            sum+=x.d;
            ontree[eid]=1;
            ontree[eid^1]=1;
        }
        cnt++;
        for(int i=head[u];i!=-1;i=edges[i].next){
            Edge &e=edges[i];
            if(!vis[e.to]) Q.push(HeapNode(e.to, e.dist, i));
        }
    }
    return sum;
}
vector<int> nodes;
int maxcost[maxn][maxn];
void dfs(int u,int fa, int dist){
    for(int i=0;i<nodes.size();i++){
        int v=nodes[i];
        maxcost[u][v]=maxcost[v][u]=max(maxcost[v][fa],dist);
    }
    nodes.push_back(u);
    for(int i=head[u];i!=-1;i=edges[i].next)
    if(ontree[i]){
        Edge &e=edges[i];
        if(e.to==fa) continue;
        dfs(e.to,u,e.dist);
    }
}
int main(){
    int T;
    int cas=0;
    int u, v, w;


    scanf("%d",&T);
    while(T--){
        scanf("%d%d",&n,&m);
        Init();
        for(int i=0;i<m;i++){
            scanf("%d%d%d",&u, &v, &w);
            u--, v--;
            Add_Edge(u,v,w);
            Add_Edge(v,u,w);
        }
        int ans1=Prim();
        mm(maxcost,0);
        nodes.clear();
        dfs(0,-1,0);
        int ans2=Inf;
        for(int i=0;i<ecnt;i+=2)
        if(!ontree[i]){
            Edge &e=edges[i];
            u=e.from;
            v=e.to;
            ans2=min(ans2, ans1-maxcost[u][v]+e.dist);
        }
        printf("%d %d\n",ans1, ans2);
    }



    return 0;
}