标签:hdu3371 最小生成树 kruskal prim connect the cities
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#include <stdio.h>
#include <string.h>
#define MAX 550
#define INF 100000000
int graph[MAX][MAX] ;
int prim(int n)
{
int sum = 0 ,lowCost[MAX] ;
bool visited[MAX] ;
memset(visited,false,sizeof(visited)) ;
for(int i = 1 ; i <= n ; ++i)
{
lowCost[i] = graph[1][i] ;
}
visited[1] = true ;
for(int i = 1 ; i < n ; ++i)
{
int min = INF , index = -1 ;
for(int j = 1 ; j <= n ; ++j)
{
if(!visited[j] && min>lowCost[j])
{
min = lowCost[j] ;
index = j ;
}
}
if(index == -1)
{
if(i < n)
{
return INF ;
}
break ;
}
sum += lowCost[index] ;
visited[index] = true ;
for(int j = 1 ; j <= n ; ++j)
{
if(!visited[j] && lowCost[j]>graph[index][j])
{
lowCost[j] = graph[index][j] ;
}
}
}
return sum ;
}
int main()
{
int t ;
scanf("%d",&t);
while(t--)
{
int n , m , k;
scanf("%d%d%d",&n,&m,&k) ;
for(int i = 1 ; i <= n ; ++i)
{
graph[i][i] = 0 ;
for(int j = 1 ; j < i ; ++j)
{
graph[i][j] = graph[j][i] = INF ;
}
}
for(int i = 0 ; i < m ; ++i)
{
int x, y ,w ;
scanf("%d%d%d",&x,&y,&w) ;
if(w<graph[x][y])
{
graph[x][y] = graph[y][x] = w;
}
}
int p[MAX] ;
for(int i = 0 ; i < k ; ++i)
{
int t ;
scanf("%d",&t);
for(int j = 0 ; j < t ; ++j)
{
scanf("%d",&p[j]);
}
for(int j = 0 ; j < t ; ++j)
{
for(int r = 0 ; r < j ; ++r)
{
graph[p[j]][p[r]] = graph[p[r]][p[j]] = 0 ;
}
}
}
int sum = prim(n) ;
if(sum >= INF)
{
puts("-1") ;
}
else
{
printf("%d\n",sum) ;
}
}
return 0 ;
}#include <cstdio>
#include <algorithm>
#include <cstring>
#define MAX 550
#define INF 1000000000
using namespace std ;
struct Edge{
int x , y , w ;
}edge[MAX*MAX];
bool cmp(const Edge &e1 , const Edge &e2)
{
return e1.w<e2.w ;
}
int f[MAX] ;
int find(int x)
{
int r = x ;
while(r != f[r])
{
r = f[r] ;
}
int temp ;
while(x != f[x] )
{
temp = f[x] ;
f[x] = r ;
x = temp ;
}
return r ;
}
void init()
{
for(int i = 0 ; i < MAX ; ++i)
{
f[i] = i ;
}
}
int kruskal(int n , int m)
{
sort(edge,edge+n,cmp) ;
init();
int sum = 0 ,count = 0;
for(int i = 0 ; i < n ; ++i)
{
int x = find(edge[i].x) , y = find(edge[i].y) ;
if(x != y)
{
count++ ;
sum += edge[i].w;
f[x] = f[y] ;
}
}
if(count<m-1)
{
return INF ;
}
return sum ;
}
int main()
{
int t ;
scanf("%d",&t);
while(t--)
{
int n , m , k;
scanf("%d%d%d",&n,&m,&k) ;
int index = 0 ;
for(int i = 0 ; i < m ; ++i)
{
int x, y ,w ;
scanf("%d%d%d",&x,&y,&w) ;
edge[index].x = x , edge[index].y = y , edge[index++].w = w ;
}
int p[MAX] ;
for(int i = 0 ; i < k ; ++i)
{
int t ;
scanf("%d",&t);
for(int j = 0 ; j < t ; ++j)
{
scanf("%d",&p[j]);
}
for(int j = 0 ; j < t ; ++j)
{
for(int r = 0 ; r < j ; ++r)
{
edge[index].x = p[j] , edge[index].y = p[r] , edge[index++].w = 0 ;
}
}
}
int sum = kruskal(index,n) ;
if(sum >= INF)
{
puts("-1") ;
}
else
{
printf("%d\n",sum) ;
}
}
return 0 ;
}
hdu 3371 Connect the Cities Prim + Kruskal两种算法分别AC 水过~~~~
标签:hdu3371 最小生成树 kruskal prim connect the cities
原文地址:http://blog.csdn.net/lionel_d/article/details/43916653