#include<bits/stdc++.h>
#define ns "-1"
#define fs(i,x,y,z) for(ll i=x;i<=y;i+=z)
#define ft(i,x,y,z) for(ll i=x;i>=y;i+=z)
#define ll long long
#define ull unsigned long long
#define db double
#define ms(a,b) memset(a,b,sizeof(a))
#define sz(a) sizeof(a)
using namespace std;
const int rw[]={-1,0,1,0,-1,1,-1,1},cl[]={0,1,0,-1,-1,1,1,-1};
const int N=1000001,inf=0x7f7f7f7f;
struct bian{
int u,v,w;
}a[N];
inline int read(){
int date=0,w=1;char c=0;
while(c<'0'||c>'9'){if(c=='-')w=-1;c=getchar();}
while(c>='0'&&c<='9'){date=date*10+c-'0';c=getchar();}
return date*w;
}
bool cmp(bian a,bian b){
return a.w<b.w;
}
int n,m,fa[N],ans;
int find(int x){
if(fa[x]==x) return x;
return fa[x]=find(fa[x]);
}
void merge(int u,int v){
u=find(u);
v=find(v);
fa[max(u,v)]=min(u,v);
}
int finding=1,now=1;
void kruskal(){
while(finding<=n-1){
bool ak=0;
while(!ak){
if(find(a[now].u)!=find(a[now].v)){
merge(a[now].u,a[now].v);
ak=1;
ans+=a[now].w;
finding++;
}
now++;
if(now>m&&!ak){
return;
}
}
//cout<<"OK\n";
}
}
int main(){
//freopen("p3366_2.in","r",stdin);
//freopen("qwq.txt","w",stdout);
n=read(),m=read();
if(m<n-1){
printf("orz");
return 0;
}
fs(i,1,n,1) fa[i]=i;
fs(i,1,m,1){
a[i].u=read();
a[i].v=read();
a[i].w=read();
//printf("OK%d\n",i);
}
//printf("OKK\n");
//system("pause");
sort(a+1,a+m+1,cmp);
//printf("OK\n");
kruskal();
if(finding==n) printf("%d",ans);
else printf("orz");
return 0;
}
Kruskal
发布于
2020-04-17
|
3分钟
|
360字数
0%
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