UVA 10600 ACM Contest and Blackout(最小生成树and次小生成树)

来源：互联网发布：中老年人学英语软件编辑：程序博客网时间：2024/05/01 07:27
拿的最小瓶颈路LCA模板做的，感觉好浪费。
#include<iostream>  #include<cstring>  #include<vector>  #include<algorithm>  using namespace std;  const int maxn=100+5;  const int maxm=10000+5;  const int logmax=20;  const int inf=1000000000;  int fa[maxn],cost[maxn],dep[maxn],anc[maxn][logmax],maxcost[maxn][logmax];  int n,m;  struct edge{      int u,v,w;      edge(int u=0,int v=0,int w=0): u(u),v(v),w(w) {}      bool operator < (const edge &rhs) const {          return w<rhs.w;      }  }e[maxm];  vector<int> G[maxn];  vector<vector<edge> > nG(maxn);  int pa[maxn];  int vis[maxn];  int map[maxn][maxn];int findset(int x) {return pa[x]==x?x:findset(pa[x]);}  int kruskal(int c)  {      int mst=0;    sort(e,e+c);      for(int i=0;i<c;i++)      {          int root1=findset(e[i].u);          int root2=findset(e[i].v);          if(root1==root2) continue;          mst+=e[i].w;        map[e[i].u][e[i].v]=map[e[i].v][e[i].u]=0;        pa[root2]=root1;          nG[e[i].u].push_back(edge(e[i].u,e[i].v,e[i].w));          nG[e[i].v].push_back(edge(e[i].v,e[i].u,e[i].w));      }      return mst;}  void dfs(int u,int f,int c,int d)  {      vis[u]=1;      fa[u]=f;cost[u]=c;dep[u]=d;      for(int i=0;i<nG[u].size();i++)      {          int v=nG[u][i].v;          int c=nG[u][i].w;          if(vis[v]) continue;          dfs(v,u,c,d+1);      }  }  void preprocess()  {      for(int i=1;i<=n;i++){          anc[i][0]=fa[i];maxcost[i][0]=cost[i];          for(int j=1;(1<<j)<=n;j++){              anc[i][j]=-1;maxcost[i][j]=0;          }      }      for(int j=1;(1<<j)<=n;j++)      {          for(int i=1;i<=n;i++)          {              if(anc[i][j-1]!=-1)              {                  int a=anc[i][j-1];                  anc[i][j]=anc[a][j-1];                  maxcost[i][j]=max(maxcost[i][j-1],maxcost[a][j-1]);              }          }      }  }  int query(int p,int q)  {      int log;      if(dep[p]<dep[q]) swap(p,q);      for(log=1;(1<<log)<=dep[p];log++) ;log--;      int ans=-inf;      for(int i=log;i>=0;i--) if(dep[p]-(1<<i)>=dep[q]) {ans=max(ans,maxcost[p][i]);p=anc[p][i];}      if(p==q) return ans;      for(int i=log;i>=0;i--){          if(anc[p][i]!=-1&&anc[p][i]!=anc[q][i]){              ans=max(ans,maxcost[p][i]);p=anc[p][i];              ans=max(ans,maxcost[q][i]);q=anc[q][i];          }      }      ans=max(ans,cost[p]);      ans=max(ans,cost[q]);      return ans;  }  int main()  {      int t;    scanf("%d",&t);      while(t--)      {           scanf("%d%d",&n,&m);        memset(map,0,sizeof(map));        int c=0;          for(int i=1;i<=n;i++) {G[i].clear();nG[i].clear();pa[i]=i;}          for(int i=1;i<=m;i++) {              int x,y,w;              scanf("%d%d%d",&x,&y,&w);              G[x].push_back(y);              G[y].push_back(x);              e[c].u=x;e[c].v=y;e[c].w=w;c++;              map[x][y]=map[y][x]=w;        }          int mst=kruskal(c),cmst=inf;          memset(vis,0,sizeof(vis));          dfs(1,-1,0,0);          preprocess();          for(int i=1;i<=n;i++){            for(int j=i+1;j<=n;j++){                if(map[i][j]){                    cmst=min(cmst,mst+map[i][j]-query(i,j));                }            }        }        printf("%d %d\n",mst,cmst);    }      return 0;  }
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