HDU-1213-How Many Tables

HDU-1213-How Many Tables-并查集

水题

#include <stdio.h>
#include <stdlib.h>
#include<string.h>
int people[1001],flag[1001];
int find(int a)
{
if(people[a]==-1)
return a;
else return people[a]=find(people[a]);
}

int add(int x,int y)
{
int xroot,yroot;
xroot=find(x);
yroot=find(y);
if(xroot==yroot)
return 0;
else people[yroot]=xroot;
}

int main()
{
int i,n,m,x,y,k,t;
scanf("%d",&t);
while(t--)
{
memset(people,-1,sizeof(people));
memset(flag,0,sizeof(flag));
scanf("%d%d",&n,&m);
while(m--)
{
scanf("%d%d",&x,&y);
add(x,y);
}
for(i=1; i<=n; i++)
{
flag[find(i)]=1;
}
k=0;
for(i=1; i<=n; i++)
{
if(flag[i]==1)
k+=1;
}
printf("%d\n",k);
}
return 0;
}