最小生成树（模板）

prim模板：

int prim(){
    for(int i = 1; i <= n; i ++){
        mincost[i] = cost[1][i];
        vis[i] = false;
    }
    mincost[1] = 0;
    int res = 0;
    while(true){
        int v = -1;
        for(int i = 1; i <= n; i ++){
            if(!vis[i] && (v == -1 || mincost[i] < mincost[v]))
                v = i;
        }
        if(v == -1) break;
        vis[v] = true;
        res += mincost[v];
        for(int i = 1; i <= n; i ++){
            mincost[i] = min(mincost[i], cost[i][v]);
        }
    }

kruscal模板

void init(){
    for(int i = 0; i < maxn; i ++){
        fa[i] = i;
    }
    weight = 0;
}

struct Nod{
    int l, r, w;
}nod[maxn];
bool cmp(Nod a, Nod b){
    return a.w < b.w;
}
int find(int x){
    return x = (fa[x] == x)? x : find(fa[x]);
}
void uni(int x, int y){
    int a = find(x);
    int b = find(y);
    if(a != b){
        fa[a] = b;
    }
}
void kruscal(){
    sort(nod, nod+cnt, cmp);
    for(int i = 0; i < cnt; i ++){
        if(find(nod[i].l) != find(nod[i].r)){
            weight += nod[i].w;
            uni(nod[i].l, nod[i].r);
        }
    }
    printf("%d
",weight);
}

使用优先队列的kruscal模板

struct Nod{
    int l, r, w;
}edg;
bool operator < (Nod a, Nod b){
    return a.w > b.w;
}
int find(int x){
    return fa[x] = (fa[x] == x) ? x : find(fa[x]);
}
int kruscal(){
    int sum = 0;
    while(que.size()){
        edg = que.top();
        que.pop();
        int a = find(edg.l);
        int b = find(edg.r);
        if(a != b){
            fa[a] = b;
            sum += edg.w;
        }
    }
    return sum;
}