lightoj-1029-Civil and Evil Engineer(最小生成树+克鲁斯卡尔算法)

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#include<stdio.h>#include<string.h>#include<algorithm>using namespace std;struct Edge{int u;int v;int cost;}edge[12010];int p[110];int k=0,n;int comp1(Edge e1,Edge e2){return e1.cost<e2.cost;}int comp2(Edge e1,Edge e2){return e1.cost>e2.cost;}int find(int x)          //找到x所属集合 {if(p[x]!=x){p[x]=find(p[x]);}return p[x];}bool bin(int x,int y)   //将x y添加至一个集合中 {int g,h;g=find(x);h=find(y);if(g!=h){p[g]=h;return true;}return false;}bool judge(){int count=0;for(int i=0;i<=n;i++){if(p[i]==i)count++;}if(count>1)return false;return true;}int main(){int t,u,i,v,cost,m,res,k=0;scanf("%d",&t);while(t--){m=0;res=0;scanf("%d",&n);while(scanf("%d%d%d",&u,&v,&cost)&&(u||v||cost)){edge[m].u=u;edge[m].v=v;edge[m++].cost=cost;}for(i=0;i<=n;i++)p[i]=i;sort(edge,edge+m,comp1);for(i=0;i<m;i++){if(bin(edge[i].u,edge[i].v)){res+=edge[i].cost;if(judge())break;}}for(i=0;i<=n;i++)p[i]=i;sort(edge,edge+m,comp2);for(i=0;i<m;i++){if(bin(edge[i].u,edge[i].v)){res+=edge[i].cost;if(judge())break;}}if(res%2==0)printf("Case %d: %d\n",++k,res/2);elseprintf("Case %d: %d/2\n",++k,res);}return 0;} /*310 1 100 1 200 0 030 1 990 2 101 2 302 3 300 0 020 1 100 2 50 0 0*/

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