HDU 1213 How Many Tables 解題報告

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AC code

#include<iostream>
#include<queue>
#include<cstring>
#include<string>
#include<sstream>
#include<map>
#include<vector>
#include<cstdio>
#include<iostream>
#include<cmath>
#include<algorithm>
#include<cstdlib>
#include<stack>
#include<ctime>
using namespace std; 
#define rep(i,aa,bb) for(register int i=aa;i<=bb;i++)
#define rrep(i,aa,bb) for(register int i=aa;i>=bb;i--)
#define mset(var,val)	 memset(var,val,sizeof(var))
#define LL long long 
#define eps 0.000001
#define inf 0x7f7f7f7f
#define llinf 1e18
#define exp 0.000001
#define pai 3.141592654
#define random(x)   rand()%(x)
#define lowbit(x)   x&(-x)
inline int read()
{
	int x=0,y=1;char a=getchar();while ( a>'9' || a<'0'){if ( a=='-')y=-1;a=getchar();}
	while ( a>='0' && a<='9' ){	x=(x<<3)+(x<<1)+a-'0'; a=getchar();}return x*y;
}
#define N 30009
int n,m,fa[N]; 
int findfa(int x){
	return x == fa[ x ] ?  x : fa[x]=findfa(fa[x]);
}
void join(int a,int b){
	fa[ findfa(a) ] = findfa(b);
}
void init(){
	rep(i,0,n)	fa[i] = i; 
}
int sumfa(int x){
	int sum = 0; 
	int xfa = findfa(x);
	for (int i = 0 ; i <= n; i++)
		if ( fa[ i ] == xfa )
			sum++;
	return sum; 		
}
int main()
{
//	freopen("1.txt","r",stdin);
	srand((int)time(0));
	int T = read();
	rep(aai,1,T){
		n = read(); m = read();
		init();
		rep(ai,1,m){
			int a,b; 
			a = read(); b = read();
			join(a,b);
		}
		rep(ai,1,n)	findfa(ai);
		int sum = 0; 
		sort(fa+1,fa+n+1);
		int num = unique(fa+1,fa+n+1) - fa - 1; 
		printf("%d\n",num);
	}
	return 0;
}