HDU 1879 继续畅通工程(Prim||Kruscal模板题)

原题链接

Prim(点归并)

//异或运算：相同为假，不同为真
#include<cstdio>
#include<algorithm>
#define maxn 105
using namespace std;
int n,m,sum,flag;
int fa[maxn];
struct Edge
{
    int u,v,w;
    bool operator<(const Edge &cmp)const{
        return w<cmp.w;
    }    
}edge[maxn*maxn>>1];

int Findset(int x)
{
    if(fa[x]==x) return fa[x]=x;
    else return fa[x]=Findset(fa[x]); 
}
int main()
{
    while(scanf("%d",&n),n){
        m=(n-1)*n/2;
        for(int i=1;i<=n;i++)
            fa[i]=i;
        for(int i=0;i<m;i++){
            scanf("%d%d%d%d",&edge[i].u,&edge[i].v,&edge[i].w,&flag);
            if(flag)
                fa[edge[i].u]=edge[i].v;
        }
        sort(edge,edge+m);
        sum=0;
        for(int i=0;i<m;i++){
            int x=Findset(edge[i].u);
            int y=Findset(edge[i].v);
            if(x!=y){
                fa[x]=y;
                sum+=edge[i].w;
            }
        }
        printf("%d\n",sum); 
    }
} 

参考链接

Kruscal(边归并)

#include<cstdio>
#include<cstring>
#define INF 0x3f3f3f3f
#define maxn 105
int i,j,k,n,m,min,sum;
int lowcost[maxn],visit[maxn];
int graph[maxn][maxn];
void Prim()
{
    sum=0;
    memset(visit,0,sizeof(visit));
    visit[1]=1;
    for(i=1;i<=n;i++)
        lowcost[i]=graph[1][i];
    for(i=2;i<=n;i++){
        min=INF;
        for(j=1;j<=n;j++){
            if(!visit[j]&&min>lowcost[j]){
                min=lowcost[j];
                k=j;
            }
        }
        sum+=lowcost[k];
        visit[k]=1;
        for(j=1;j<=n;j++){
            if(!visit[j]&&lowcost[j]>graph[k][j])
                lowcost[j]=graph[k][j];
        }
    }
}

int main()
{
    int a,b,c,d;
    while(scanf("%d",&n),n){
        m=(n-1)*n/2; 
        memset(graph,INF,sizeof(graph));
        while(m--){
            scanf("%d%d%d%d",&a,&b,&c,&d);
            if(d) graph[a][b]=graph[b][a]=0;
            else graph[a][b]=graph[b][a]=c;
        }
        Prim(); 
        printf("%d\n",sum);
    }
    return 0;
}