HDU3234

尼玛这题出题人太JB NB了，乍一看以为线段树，仔细看看发现不是，查询时区间不连续

后来就搜索解题报告，才知道是并查集 ，但是又不知道咋个并，咋个查。。。ORZ，，，，蒟蒻，

题意：给出一个数值固定的数列，x0,x1,x2,……xn-1;

#include<cstdio>
#include<string.h>
#include<algorithm>
#include<cmath>
#include<vector>
#include<map>
using namespace std;
const int N=23002;
int n,val[N],father[N];
void init(int n)
{

	  for(int i=0;i<=n;i++)
		     {

		val[i]=0;
		father[i]=i;

		}
}
int find(int x)
{

	   if(x==father[x])
		{

		return x;	
		}
         int tmp=find(father[x]);
	     val[x]^=val[father[x]];
		   father[x]=tmp;
	     return father[x];
}
bool Union(int x,int y,int v)
{
	int fx=find(x);
	int fy=find(y);
	if(fx==fy)
	{
		return v==(val[x]^val[y]);
	}
    if(fy==n)
	swap(fx,fy);
	
	val[fy]=val[x]^val[y]^v;
         father[fy]=fx;
	return true;
}
int main()
{freopen("/home/kapop/pro/1.txt","r",stdin);
 freopen("/home/kapop/pro/2.txt","w",stdout);
  int Q;
  char op[12];
  char str[11];
  int x,y,v;
  int tt=1;
  int step=0;
  bool ok=true;
  while(~scanf("%d%d",&n,&Q)){
            if(n+Q==0)break;
	  printf("Case %d:\n",tt++);step=0;
	  init(n);
            ok=true;
	  while(Q--){
        scanf("%s",op);
		
		if('I'==op[0])
		{step++;
		   gets(str);
		  int cnt=sscanf(str,"%d %d %d",&x,&y,&v);
		  if(cnt==2)
		    {
		 	 v=y;y=n;
		    }
	         	if(!ok)
			continue;
		 	if(!Union(x,y,v)){
			 	ok=false;
				 printf("The first %d facts are conflicting.\n",step);
		         }
		} 
		else if('Q'==op[0]){
                      if(!ok)
			 {    int kk,ta;

				scanf("%d",&kk);
				while(kk--){
					scanf("%d",&ta);

				}

			  }
			else{

				
				int nn,pp,ans=0;
				map<int ,int>M;
				bool mn=true;
				scanf("%d",&nn);
					for(int i=1;i<=nn;i++){
						scanf("%d",&pp);
						if(!ok)continue;
						int yy=find(pp);
							ans^=val[pp];
							M[yy]++;
					  }
					if(!ok)continue;
				for(map<int ,int >::iterator it=M.begin();it!=M.end();it++)
				{
				  if(it->second %2){
				    if(it->first != n){mn=false;break;}
						
				   }							
				}
				 if(mn){
						printf("%d\n",ans);				
				}
				else{
					printf("I don't know.\n");
				


				}
			}
		}
	  }
  }
  return 0;
}