题意：给你一个整数数列，然后在给你一个数，让你在这个整数数列中寻找到一个数使得与给定数字的异或最大。

思路：把整数序列建立起一棵01字典树，然后查找即可。（还是开 ll 比较好）。

AC Code：

#include<iostream>
#include<cstring>
#include<queue>
#include<map>
#include<set>
#include<stack>
#include<cmath>
#include<cstdio>
#include<iomanip>
#include<sstream>
#include<algorithm>

using namespace std;
#define read(x) scanf("%d",&x)
#define Read(x,y) scanf("%d%d",&x,&y)
#define sRead(x,y,z)  scanf("%d%d%d",&x,&y,&z)
#define gc(x)  scanf(" %c",&x);
#define mmt(x,y)  memset(x,y,sizeof x)
#define write(x) printf("%d\n",x)
#define ios   ios::sync_with_stdio(false);cin.tie(0);
#define INF 0x3f3f3f3f
#define ll long long
const ll mod = 1e9 + 7;
#define pii pair<int,int>
#define pdd pair<double,double>
const int N = 4e5+5;
const int  M = 1e7 + 5;
int trie[M][2],tot = 1;
void Insert(ll u){
    ll p = 1;
    for(ll i = 31;i >= 0; -- i){
        int ch = (u >> i)&1;
        if(trie[p][ch] == 0) trie[p][ch] = ++tot;
        p = trie[p][ch];
    }
}
ll Search(ll u){
    ll p = 1,ans = 0;
    for(int i = 31;i >= 0;i --){
        int ch = (u >> i)&1;
        if(trie[p][!ch]) {
            if(ch == 0){
                ans += (1LL << i);
            }
            p = trie[p][!ch];
        }
        else {
            p = trie[p][ch];
            if(ch == 1) ans += (1 << i);
        }
    }
    return ans;
}
inline void init(){
    mmt(trie,0);
    tot = 1;
}
int main()
{
    //freopen("input.txt","r",stdin);
    int T;
    read(T);
    int n,m;
    for(int p = 1;p <= T;++p){
        init();
        Read(n,m);
        ll u;
        for(int i = 1;i <= n;++i){
            scanf("%lld",&u);
            Insert(u);
        }
        printf("Case #%d:\n",p);
        for(int i =1;i <= m;++i){
            scanf("%lld",&u);
            printf("%lld\n",Search(u));
        }
    }
}