双 线 程 做 题
by 警策看取 @ 2020-08-04 13:59:06
@[xiaolaoshu](/user/327971) 要不把题目都发出来让大家调算了，还不会棕
by Linune_Gump @ 2020-08-04 13:59:31
显然两帖题目、代码都不同，lz是积攒着一起发的，没毛病
by xiaolaoshu @ 2020-08-04 13:59:51
@[xiaolaoshu](/user/327971) 你没看到，他前面还发了一个最小生成树的
by Implicit @ 2020-08-04 14:00:52
哦，我只看见一个线段树的
by xiaolaoshu @ 2020-08-04 14:02:57
主页双帖 危
by 百因必有AC @ 2020-08-04 14:05:57
主页双帖 危。
by 血色黄昏 @ 2020-08-04 14:08:40
主页双帖 危
by _Rainlzy @ 2020-08-04 14:12:03
@[yhc12345](/user/141577)
by JK_LOVER @ 2020-08-04 14:30:48
```cpp
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<string>
#include<cmath>
#include<queue>
#define INF 0x3f3f3f3f
using namespace std;
typedef long long ll;
int n,m;
const int N=5010,M=2e5+10;
struct Edge {
int v,w,nxt;
}e[M<<1];
int head[N],ne;
int lc[N];
bool vis[N];
void init() {
memset(head,-1,sizeof(head));
ne=0;
}
void add_edge(int u,int v,int w) {
e[++ne].v=v;
e[ne].w=w;
e[ne].nxt=head[u];
head[u]=ne;
}
struct Node {
int id,lc;
Node(int _id,int _lc) {
id=_id;
lc=_lc;
}
bool operator<(const Node a) const{
return lc > a.lc;
}
};
priority_queue<Node> pq;
bool flag=true;
int ans;
void prim() {
memset(lc,0x3f,sizeof(lc));
lc[1]=0;
vis[1]=true;
for(int i=head[1];i!=-1;i=e[i].nxt)
{
if(lc[e[i].v]>lc[1]+e[i].w)
{
lc[e[i].v]=lc[1]+e[i].w;
pq.push(Node(e[i].v,lc[e[i].v]));
}
}
for(int i=1;i<n;i++) {
int k=-1;
while(!pq.empty())
{
k=pq.top().id;pq.pop();
if(!vis[k]) break;
}
if(k==-1) {
flag=false;
break;
}
vis[k]=true;
ans+=lc[k];
lc[k] = 0;//重要
// cout<<"id"<<k<<" lc[k] : " <<lc[k]<<endl;
for(int i=head[k];i!=-1;i=e[i].nxt)
{
if(!vis[e[i].v]&&lc[e[i].v]>lc[k]+e[i].w)
{
lc[e[i].v]=lc[k]+e[i].w;
pq.push(Node(e[i].v,lc[e[i].v]));
}
}
}
}
int main() {
init();
scanf("%d%d",&n,&m);
for(int i=1;i<=m;i++) {
int u,v,w;
scanf("%d%d%d",&u,&v,&w);
add_edge(u,v,w);
add_edge(v,u,w);
}
prim();
if(!flag) {
printf("orz");
}
else {
printf("%d\n",ans);
}
return 0;
}
```
by JK_LOVER @ 2020-08-04 14:31:00