杭电3371--Connect the Cities(最小生成树)

题目：http://acm.hdu.edu.cn/showproblem.php?pid=3371

ac:

#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;
const int INF = 0x3f3f3f3f;
int map[550][550], dis[550], vis[550];
int n, m, K;
void Prim()
{
    int sum = 0;
    memset(vis, 0, sizeof(vis));
    for(int i = 1; i <= n; i++)
        dis[i] = map[1][i];
    vis[1] = 1;
    for(int i = 1; i < n; i++)
    {
        int min = INF, temp;
        for(int j = 1; j <= n; j++)
        {
            if(!vis[j] && dis[j] < min)
            { 
                temp = j;
                min = dis[j];
            }
        }
        vis[temp] = 1; 
        if(min == INF){
            printf("-1
");
            return;
        }
        sum += min;
        for(int j = 1; j <=n; j++)
        {
            if(!vis[j] && dis[j] > map[temp][j])
                dis[j] = map[temp][j];
        }
    }
    printf("%d
",sum);
}
int main()
{
    int T;
    scanf("%d", &T);
    while(T--)
    {
        scanf("%d %d %d", &n, &m, &K);
        for(int i = 1; i <= n; i++)
            for(int j = 1; j <= n; j++)
                map[i][j]=(i==j?0:INF);
        int u, v, w;
        for(int k = 0; k < m; k++){
            scanf("%d %d %d", &u, &v, &w);
            if(map[u][v] > w)
                map[u][v] = map[v][u] = w;
        }
        int a[110];
        for(int Q = 0; Q < K; Q++)
        {
            int L;
            scanf("%d", &L);
            for(int i = 0; i < L; i++)
                scanf("%d", &a[i]);
            for(int b = 0; b < L; b++)
                for(int c = 0; c <= b; c++)
                    map[a[b]][a[c]]=map[a[c]][a[b]]=0;
        }
        Prim();
    }
    return 0; 
} 

Kl 超时； 卡不过。

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
struct Rode
{
    int a, b, Val;
} num[25050];
int cmp(Rode a, Rode b)
{
    return a.Val < b.Val;
}
int n, m, k; 
int father[550], Yh[550], cnt;
void init()
{
    for(int i = 1; i <= n; i++){
        father[i] = i;
        Yh[i] = 0;
    }
    cnt = n - 1;    
} 
int find(int a)
{
    int r, j, k;
    r = a;
    while(r != father[r])
        r = father[r];
    j = a;
    while(j != r)
    {
        k = father[j]; 
        father[j] = r;
        j = k;
    }
    return r;
}
bool mercy(int a, int b)
{
    if(a == -1)
        return false;
    int Q = find(a); 
    int p = find(b);
    if(Q != p)
    {
        if(Yh[Q] < Yh[p])
        {
            Yh[p] += Yh[Q];
            father[Q] = p; 
        } 
        else
        {
            Yh[Q] += Yh[p];
            father[p] = Q;
        }
        cnt--;
    //    father[Q] = p;
        return true;    
    } 
    return false;
}
/* bool Judge()
{
    int sum = 0;
    for(int i = 1; i <= n; i++)
        if(father[i] == i)
            sum++;
    if(sum == 1)
        return true;
    else
        return false;
} */
int main()
{
    int T;
    scanf("%d", &T);
    while(T--)
    {
        scanf("%d %d %d", &n, &m, &k);
        init();
        for(int i = 0; i < m; i++)
            scanf("%d %d %d", &num[i].a, &num[i].b, &num[i].Val);
        int Q;
        for(int j = 0; j < k; j++)
        {
            scanf("%d", &Q);
            int pre = -1, Yes;
            for(int k = 0; k < Q; k++){
                scanf("%d", &Yes);
                    mercy(pre, Yes);
                pre = Yes;
            }            
        }
        sort(num, num + m, cmp);
        int total = 0;
        for(int i = 0; i < n; i++)
        {
            if(mercy(num[i].a, num[i].b))
                total += num[i].Val; 
        }
        //if(Judge())
        if(cnt == 0)
            printf("%d
", total);
        else
            printf("-1
");
    }
    return 0;
}