UVALive 4487 异或 并查集

题目点这

位运算很强大啊

题解看着

这个题解中文讲解很详细，个人感觉代码上稍微有点繁琐，但总体很容易看懂

其他几个题解，代码看一眼，先来十几个define，，，GG

#include<cstdio>#include<cstring>#include<iostream>using namespace std;const int N=23333,T=N-10;int n,Q,op,p,q,va,k,ans,cas=1;int home[N],v[N],a[20],vis[N];bool ok;int FIND(int x){    if (home[x]==x)return x;    int kk=home[x];    home[x]=FIND(home[x]);    v[x]^=v[kk];    return home[x];}bool check(int i,int j,int va){    int r1=FIND(i),r2=FIND(j);    if (r1==r2)return (v[i]^v[j])==va;    if (r1==T ) swap(r1,r2);    home[r1] = r2;    v[r1]=v[i]^v[j]^va;    return 1;}int main(){    //freopen("fuck.in","r",stdin);    for (;scanf("%d%d",&n,&Q)==2;cas++){        if (n==0&&Q==0)break;        printf("Case %d:\n",cas);        for (int i=0;i<=n+1;i++)home[i]=i;        memset(v,0,sizeof(v));        home[T]=T;        ok=1; op=0;        for (int time=0;time<Q;time++){            char ch[2]; scanf("%s",ch);            if (ch[0]=='I') {                char st[55]; gets(st); op++;                if (sscanf(st,"%d%d%d",&p,&q,&va)==2)                     { va = q ; q = T ; }                if (!ok)continue;                if (!check(p,q,va)){                    ok=0;                    printf("The first %d facts are conflicting.\n",op);                }            }            else {                ans=0;  scanf("%d",&k);                memset(vis,0,sizeof(vis));                for (int i=0;i<k;i++){                    scanf("%d",&a[i]);                    if (!ok)continue;                    int root=FIND(a[i]);                    ans^=v[a[i]];                    a[i]=root;                    vis[root]^=1;                }                if (!ok)continue;                bool okk=1;                for (int i=0;i<k;i++)                    if (vis[a[i]]&&a[i]!=T)okk=0;                if (okk)printf("%d\n",ans);                else puts("I don't know.");            }        }        puts("");    }    return 0;}

hust抽风了一下

最后是这样

两发WA是因为从pdf里面复制 I don’t know 的时候
粘到txt里面就变成了I don‘t know，坑爹啊