hduoj-1301 Jungle Roads(最小生成树-克鲁斯卡尔和普里姆求解）

#include<cstdio>
#include<cmath>
#include<cstring>
#include<iostream>
#include<cstdlib>
#include<algorithm>
#include<string>
#include<stack>
#include<queue>
#include<map>
using namespace std;
const int MAX=100;
const int INF=100000;
int n;//村庄数
int G[MAX][MAX],d[MAX];
bool isVisit[MAX]={false};
int prim(){
    fill(d,d+MAX,INF);
    d[0]=0;
    int ans=0;
    for(int i=0;i<n;i++){
        int u=-1,MIN=INF;
        for(int j=0;j<n;j++){
            if(isVisit[j]==false&&d[j]<MIN){
                u=j;
                MIN=d[j];
            }
        }
        if(u==-1) return -1;
        isVisit[u]=true;
        ans+=d[u];
        for(int v=0;v<n;v++){
            if(isVisit[v]==false&&G[u][v]!=INF&&d[v]>G[u][v]){
                d[v]=G[u][v];
            }
        }
    }
    return ans;
}
int main(){
    while(scanf("%d",&n)&&n!=0){
        getchar();
        fill(G[0],G[0]+MAX*MAX,INF);
        int temp1,temp2;
        char c1[10],c2[10];
        for(int i=0;i<n-1;i++){
            scanf("%s %d",&c1,&temp1);
            for(int j=0;j<temp1;j++){
                scanf("%s %d",&c2,&temp2);
                G[c1[0]-‘A‘][c2[0]-‘A‘]=G[c2[0]-‘A‘][c1[0]-‘A‘]=temp2;
            }
        }
        int ans=prim();
        printf("%d\n",ans);
    }

    return 0;
}

#include<cstdio>
#include<cmath>
#include<cstring>
#include<iostream>
#include<cstdlib>
#include<algorithm>
#include<string>
#include<stack>
#include<queue>
#include<map>
using namespace std;
const int MAX=100;
const int MAXE=100;
const int INF=1000000000;
int d[MAX],father[MAX];
int n,m=0;
bool isVisit[MAX]={false};
struct edge{
    int node1,node2;
    int weight;
}E[MAXE];
bool cmp(edge e1,edge e2){
    return e1.weight<e2.weight;
}
int findFather(int x){
    int a=x;
    while(x!=father[x]){
        x=father[x];
    }
    while(a!=father[a]){
        int temp=a;
        a=father[a];
        father[temp]=x;
    }
    return x;
}
int kruskal(){
    int ans=0,num_edge=0;
    for(int i=0;i<n;i++)
        father[i]=i;
    sort(E,E+m,cmp);
    for(int i=0;i<m;i++){
        int f1=findFather(E[i].node1);
        int f2=findFather(E[i].node2);
        if(f1!=f2){
            father[f1]=f2;
            ans+=E[i].weight;
            num_edge++;
            //边数等于顶点数-1结束
            if(num_edge==n-1) break;
        }
    }
    if(num_edge!=n-1) return -1;
    else return ans;
}

int main(){
    while(scanf("%d",&n)&&n!=0){
        getchar();
        //fill(G[0],G[0]+MAX*MAX,INF);
        char c1[10],c2[10];
        int temp1,temp2;
        for(int i=0;i<n-1;i++){
            scanf("%s %d",&c1,&temp1);
            for(int j=0;j<temp1;j++){
                scanf("%s %d",&c2,&temp2);
                E[m].node1=c1[0]-‘A‘;
                E[m].node2=c2[0]-‘A‘;
                E[m].weight=temp2;
                m++;
            }
        }
        int ans=kruskal();
        printf("%d\n",ans);

    }

    return 0;
}