#include<cstdio>
const int N = 1e6 + 5;
struct Trie{
int root, id;
bool bit[32];
struct Node{
int val, siz, ch[2];
Node(){ ch[0] = ch[1] = -1, val = siz = 0; }
}node[N];
void get(int x){
for(int i = 0; i < 32; ++i, x >>= 1) bit[i] = x & 1;
}
void init(){
for(int i = 0; i <= id; ++i){
node[i].ch[0] = node[i].ch[1] = -1;
node[i].val = node[i].siz = 0;
}
id = root = 0;
}
void insert(int x){
get(x);
int u = root;
for(int i = 31; i >= 0; --i){
if(node[u].ch[bit[i]] == -1) node[u].ch[bit[i]] = ++id;
u = node[u].ch[bit[i]];
++node[u].siz;
}
node[u].val = x;
}
int find(int x){ // 返回与x异或最大的数
get(x);
int u = root;
for(int i = 31; i >= 0; --i){
int s1 = node[u].ch[!bit[i]], s2 = node[u].ch[bit[i]];
if(s1 != -1 && node[s1].siz > 0) u = s1;
else if(s2 != -1 && node[s2].siz > 0) u = s2;
else return x; // 注意根据需要调整返回值
}
return node[u].val;
}
void del(int x){
get(x);
int u = root;
for(int i = 31; i >= 0; --i){
u = node[u].ch[bit[i]];
--node[u].siz;
}
}
}trie;