cf842d Vitya and Strange Lesson

#include <iostream>
#include <cstdio>
using namespace std;
int s[2000005][2], cnt, n, m, x, uu, ans, dep[2000005], siz[2000005];
void ins(){
	int u=0;
	for(int i=19; i>=0; i--){
		int t=(x&(1<<i))>0;
		if(!s[u][t])	s[u][t] = ++cnt;
		u = s[u][t];
	}
}
void dfs(int o){
	if(o)	siz[o] = 1;
	if(s[o][0])	dfs(s[o][0]);
	if(s[o][1])	dfs(s[o][1]);
	siz[o] += siz[s[o][0]] + siz[s[o][1]];
}
void getAns(){
	int u=0;
	for(int i=19; i>=0; i--){
		int t=(x&(1<<i))>0;
		if(siz[s[u][t]]!=(1<<(i+1))-1){
			ans |= t<<i;
			u = s[u][t];
		}
		else{
			ans |= (t^1)<<i;
			u = s[u][t^1];
		}
	} 
}
int main(){
	cin>>n>>m;
	for(int i=1; i<=n; i++){
		scanf("%d", &x);
		ins();
	}
	x = 0;
	dfs(0);
	while(m--){
		ans = 0;
		scanf("%d", &uu);
		x ^= uu;
		getAns();
		printf("%d\n", ans^x);
	}
	return 0;
}