最小生成树prim与kruskal

prim

#include<bits/stdc++.h>
using namespace std;
#define ll long long 
#define up(i,a,n) for(int i=a;i<=n;i++)
#define pb push_back
const int inf=0x3f3f3f3f;
const int maxn=5e3+10;
bool vis[maxn];
int n,m,tot,ans,dis[maxn];
struct node
{
	int to,cap;
	friend bool operator < (node a,node b)
	{
		return a.cap>b.cap;
	}
};
vector<node>g[maxn];
void add(int x,int y,int z)
{
	g[x].pb(node{y,z});
	g[y].pb(node{x,z});
}
void init()
{
	scanf("%d %d",&n,&m);
	int u,v,ca;
	up(i,1,m)
	{
		scanf("%d %d %d",&u,&v,&ca);
		add(u,v,ca);
	}
}
int prim()
{   int sum=0;
    memset(vis,false,sizeof(vis));
    priority_queue<node>q;
    q.push(node{1,0});
while(!q.empty())
{
	node s=q.top();q.pop();
	if(vis[s.to])continue;
	vis[s.to]=true;
	sum+=s.cap;
	for(auto k:g[s.to])
	{
		if(!vis[k.to])
		q.push(k);
	}
	
}
return sum;
}
int main()
{
	init();
	cout<<prim()<<endl;
}

kruskal

#include<bits/stdc++.h>
using namespace std;
#define ll long long 
#define up(i,a,n) for(int i=a;i<=n;i++)
#define pb push_back
const int maxn=5e4+10;
int n,m,fa[maxn],ans,cnt;
struct node{
int u,v,cost;
}edge[maxn<<2];
int find(int x)
{
	while(x!=fa[x])x=fa[x]=fa[fa[x]];
	return x;
}
int cmp(node a,node b)
{
	return a.cost<b.cost;
}
void init()//建图 
{
	scanf("%d %d",&n,&m);
	up(i,1,m)
	{
		scanf("%d%d%d",&edge[i].u,&edge[i].v,&edge[i].cost);
	}
	up(i,1,n)fa[i]=i;
}
void kruskal()
{
   sort(edge,edge+m,cmp);//给权值排序 
   for(int i=0;i<m;i++)
   {
   	   int du=find(edge[i].u),dv=find(edge[i].v);
   	   if(du==dv)continue;//查找是否成环 
   	   ans+=edge[i].cost;
   	   fa[dv]=du;
   	   if(++cnt==n-1)break;//当找到了之后 
   }
}
int main()
{
	init();
	kruskal();
	cout<<ans<<endl;
}