POJ 2492 A Bug's Life（并查集）

同性恋的虫子~~

大神的代码都看不懂%>_<%

wa了几次后，学《挑战程序设计竞赛》食物链的做法

1~n表示一种性别，n+1~2*n表示另一种性别

如果x虫子和y虫子搞（...），就看x和y是不是在同一个集合，如果是的话就有特殊的虫子

不是的话就合并x和y+n，x+n和y

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#include<cmath>
#include<queue>
#include<map>
#include<set>
using namespace std;

#define mxn 4020
#define ym 100200
#define inf 0x3f3f3f3f
#define eps 1e-8
#define LL long long 
#define ULL unsigned long long
#define MP make_pair
#define pb push_back

int fa[mxn];

void init() {
	for( int i = 0; i < mxn; ++i )
		fa[i] = i;
}

int find( int x ) {
	if( fa[x] != x ) 
		fa[x] = find( fa[x] );
	return fa[x];
}
bool same( int u, int v ) {
	int fu = find( u );
	int fv = find( v );
	return fu == fv;
}
void un( int u, int v ) {
	int fu = find( u );
	int fv = find( v );
	fa[fu] = fv;
}
int main() {
	int cas;
	int kk = 1;
	scanf( "%d", &cas );
	while( cas-- ) {
		init();
		int n, m;
		scanf( "%d%d", &n, &m );
		bool flag = 1;
		int u, v;
		for( int i = 1; i <= m; ++i ) {
			scanf( "%d%d", &u, &v );
			if( flag ) {
				if( same( u, v ) || same( v + n, u + n ) )
					flag = 0;
				else {
					un( u, v + n );
					un( v, u + n );
				}
			}
		}
		printf( "Scenario #%d:\n", kk++ );
		if( flag )
			printf( "No suspicious bugs found!\n\n" );
		else
			printf( "Suspicious bugs found!\n\n" );
	}
	return 0;
}