Kruskal || BZOJ 1601: [Usaco2008 Oct]灌水 || Luogu P1550 [USACO08OCT]打井Watering Hole
题面：P1550 [USACO08OCT]打井Watering Hole
题解：无
代码：
1 #include<cstdio> 2 #include<cstring> 3 #include<iostream> 4 #include<algorithm> 5 #define ll long long 6 using namespace std; 7 const int maxn=350; 8 int N,W[maxn],fa[maxn],num_edge=0,edge_head[maxn]; 9 ll Z,ans; 10 struct Edge{int from,to,nx;ll dis;}edge[2*maxn*maxn]; 11 inline void Add_edge(int from,int to,ll dis){ 12 edge[++num_edge].nx=edge_head[from]; 13 edge[num_edge].from=from; 14 edge[num_edge].to=to; 15 edge[num_edge].dis=dis; 16 edge_head[from]=num_edge; 17 return; 18 } 19 inline int getf(int n){ 20 if(fa[n]==n)return n; 21 fa[n]=getf(fa[n]); 22 return fa[n]; 23 } 24 inline bool cmp(const Edge&a,const Edge&b){return a.dis<b.dis;} 25 void Kruskal(){ 26 int cnt=0; 27 for(int i=0;i<=N;i++)fa[i]=i; 28 sort(edge+1,edge+num_edge+1,cmp); 29 for(int i=1;i<=num_edge;i++){ 30 int x=edge[i].from,y=edge[i].to; 31 int fx=getf(x),fy=getf(y); 32 if(fa[x]!=fa[y]){ 33 cnt++; 34 fa[fx]=fy; 35 ans+=edge[i].dis; 36 } 37 } 38 return; 39 } 40 int main(){ 41 scanf("%d",&N); 42 for(int i=1;i<=N;i++)scanf("%d",&W[i]); 43 for(int i=1;i<=N;i++)Add_edge(0,i,W[i]); 44 for(int i=1;i<=N;i++) 45 for(int j=1;j<=N;j++){ 46 scanf("%lld",&Z); 47 Add_edge(i,j,Z); 48 } 49 Kruskal(); 50 printf("%lld\n",ans); 51 return 0; 52 }
By:AlenaNuna
