模板最小生成树Kruskal

Posted 2020-10-12 Driver_Lao

洛谷3366

 1 #include<cstdio>
 2 #include<algorithm>
 3 using namespace std;
 4 const int maxn=5010,maxm=200010;
 5 int n,m,fa[maxn],tot=0,ans=0;
 6 struct edge{int x,y,dis;}a[maxm];
 7 void read(int &k){
 8     k=0; int f=1; char c=getchar();
 9     while (c<‘0‘||c>‘9‘)c==‘-‘&&(f=-1),c=getchar();
10     while (‘0‘<=c&&c<=‘9‘)k=k*10+c-‘0‘,c=getchar();
11     k*=f;
12 }
13 bool cmp(edge a,edge b){return a.dis<b.dis;}
14 int find(int x){return fa[x]==x?x:fa[x]=find(fa[x]);}
15 int main(){
16     read(n); read(m);
17     for (int i=1;i<=n;i++) fa[i]=i;
18     for (int i=1;i<=m;i++) read(a[i].x),read(a[i].y),read(a[i].dis);
19     sort(a+1,a+m+1,cmp);
20     for (int i=1,x,y;i<=m;i++){
21         if (find(x=a[i].x)!=find(y=a[i].y)) fa[find(x)]=find(y),ans+=a[i].dis,tot++;
22         if (tot==n-1) break;
23     }
24     if (tot==n-1) printf("%d",ans); else printf("orz");
25 }

View Code