最小生成树Prim算法模板

#include<iostream>
#include<cstdio>
#include<climits>
int head[105],vet[10005],w[10005],next[10005],num;
int dist[105];
bool f[105];
void addedge(int x,int y,int c) {
num+
4000
+;
vet[num]=y;
w[num]=c;
next[num]=head[x];
head[x]=num;
}
int main() {
int n,m,ans=0;
std::cin >> n >> m;
for (int i=1;i<=m;i++) {
int x,y,c;
scanf("%d%d%d",&x,&y,&c);
addedge(x,y,c);
addedge(y,x,c);
}
for (int i=1;i<=n;i++) dist[i]=INT_MAX;
dist[1]=0;
for (int i=1;i<=n;i++) {
int mindist=INT_MAX,p=0;
for (int j=1;j<=n;j++)
if (!f[j] && mindist>dist[j]) {
mindist=dist[j];
p=j;
}
f[p]=true;
ans+=dist[p];
for (int e=head[p];e!=0;e=next[e])
if (!f[vet[e]])
dist[vet[e]]=std::min(dist[vet[e]],w[e]);
}
std::cout << ans;
return 0;
}

#include<iostream>
#include<cstdio>
#include<climits>
#include<queue>
struct node {
int p,weight;
bool operator<(const node &a)const {
return weight>a.weight;
}
};
int head[100005],vet[200005],w[200005],next[200005],num;
int dist[100000];
bool f[100005];
void addedge(int x,int y,int c) {
num++;
vet[num]=y;
w[num]=c;
next[num]=head[x];
head[x]=num;
}
int main() {
int n,m;
int ans=0;
std::cin >> n >> m;
for (int i=1;i<=m;i++) {
int x,y,c;
scanf("%d%d%d",&x,&y,&c);
addedge(x,y,c);
addedge(y,x,c);
}
for (int i=1;i<=n;i++) dist[i]=INT_MAX;
dist[1]=0;
std::priority_queue<node> qu;
node newnode;
newnode.weight=0;
newnode.p=1;
while (!qu.empty()) qu.pop();
qu.push(newnode);
for (int i=1;i<=n;i++) {
while (f[qu.top().p]) qu.pop();
newnode=qu.top();
qu.pop();
f[newnode.p]=true;
ans+=newnode.weight;
for (int e=head[newnode.p];e!=0;e=next[e])
if (!f[vet[e]] && dist[vet[e]]>w[e]) {
newnode.p=vet[e];
newnode.weight=w[e];
dist[vet[e]]=w[e];
qu.push(newnode);
}
}
std::cout << ans;
return 0;
}

#include<iostream>
#include<cstdio>
#include<climits>
struct node {
int p,weight;
bool operator<(const node &a)const {
return weight<a.weight;
}
};
int head[100005],vet[200005],w[200005],next[200005],num;
int dist[100005],hsize,po[100005];
node heap[200005];
bool f[100005];
void addedge(int x,int y,int c) {
num++;
vet[num]=y;
w[num]=c;
next[num]=head[x];
head[x]=num;
}
void sw(int p1,int p2) {
po[heap[p1].p]=p2;
po[heap[p2].p]=p1;
node tmp=heap[p1];
heap[p1]=heap[p2];
heap[p2]=tmp;
}
void Up(int p) {
while (p>1) {
if (heap[p]<heap[p/2]) {
sw(p,p/2);
p/=2;
}
else break;
}
}
void Down(int p) {
while (p*2<=hsize) {
int Min=p;
if (heap[p*2]<heap[Min]) Min=p*2;
if (p*2<hsize && heap[p*2+1]<heap[Min]) Min=p*2+1;
if (Min != p) {
sw(p,Min);
p=Min;
}
else break;
}
}
void decrease_key(int t,int v) {
heap[t].weight=v;
Up(t);
}
void heap_push(node res) {
heap[++hsize]=res;
po[res.p]=hsize;
Up(hsize);
}
node heap_pop() {
sw(1,hsize);
hsize--;
Down(1);
po[heap[hsize+1].p]=0;
return heap[hsize+1];
}
int main() {
int n,m;
int ans=0;
std::cin >> n >> m;
for (int i=1;i<=m;i++) {
int x,y,c;
scanf("%d%d%d",&x,&y,&c);
addedge(x,y,c);
addedge(y,x,c);
}
for (int i=1;i<=n;i++) dist[i]=INT_MAX;
dist[1]=0;
heap_push((node){1,0});
for (int i=1;i<=n;i++) {
node newnode=heap_pop();
f[newnode.p]=true;
ans+=newnode.weight;
for (int e=head[newnode.p];e!=0;e=next[e])
if (!f[vet[e]] && dist[vet[e]]>w[e]) {
if (po[vet[e]]==0) heap_push((node){vet[e],w[e]});
decrease_key(po[vet[e]],w[e]);
dist[vet[e]]=w[e];
}
}
std::cout << ans;
return 0;
}