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;
}