九度：1017<并查集><Kruskal><MST>

来源：互联网发布：报表软件架构编辑：程序博客网时间：2024/05/23 02:04

浙大2006年研究生机试

畅通工程：最小生成树

#include <stdio.h>#include <iostream>#include <algorithm>#include <string.h>using namespace std;struct Road{int s;int e;int len;bool operator < (const Road & A) const{return len < A.len;}};int fa[110];int Getfa(int x){if ( x == fa[x])return x;fa[x] = Getfa(fa[x]);return fa[x];}int main(){#ifdef ONLINE_JUDGE#else    freopen("E:\\in.txt", "r", stdin);#endifint n;while(scanf("%d", &n) && n){int i, nr = n*(n-1)/2;for(i=1; i<=n; i++){fa[i] = i;}Road rb[10000];for(i=0; i<nr; i++){scanf("%d %d %d", &rb[i].s, &rb[i].e, &rb[i].len);}sort(rb, rb+nr);int ans=0;for(i=0; i<nr; i++){if(Getfa(rb[i].s) != Getfa(rb[i].e)){//村未连通fa[Getfa(rb[i].s)] = Getfa(rb[i].e);//则连通ans += rb[i].len;}}cout << ans << endl;}//whilereturn 0;}

第二次做

#include <stdio.h>#include <algorithm>#define SIZE 101#define MAXSIZE 100*99/2+10using namespace std;int fa[SIZE];struct Edge{    int a, b;    int cost;    bool operator < (const Edge& A) const{        return cost < A.cost;    }};int Getfa(int x){    if(x == fa[x])        return x;    else        fa[x] = Getfa(fa[x]);    return fa[x];}int main(){#ifdef ONLINE_JUDGE#elsefreopen("E:\\in.txt", "r", stdin);//freopen("E:\\out.txt", "w", stdout);#endif    int n;    while(scanf("%d", &n) && n)    {        int num = n*(n-1)/2;        Edge edge[MAXSIZE];        for(int i=1; i<=n; i++)        {            fa[i]=i;        }        for(int i=0; i<num; i++)        {            scanf("%d%d%d", &edge[i].a,&edge[i].b, &edge[i].cost);        }        sort(edge, edge+num);        int x, y, ans=0;        for(int i=0;i<num;i++)        {            x=Getfa(edge[i].a);            y=Getfa(edge[i].b);            if(x != y){                fa[x] = y;                ans += edge[i].cost;            }        }        printf("%d\n", ans);    }    return 0;}

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