Vasiliys_Multiset.cpp

#include "bits/stdc++.h"
using namespace std;

const int N  = 200000 + 50;
const int LN = 32;

int cur, lc[N * LN], rc[N * LN], leaves[N * LN];

inline void update(int node, int i, int val, int add){
	leaves[node] += add;
	if(i == -1) return;
	if(val & (1 << i)){
		if(rc[node] == -1){
			rc[node] = ++cur;
		}
		update(rc[node], i - 1, val, add);
	}
	else{
		if(lc[node] == -1){
			lc[node] = ++cur;
		}
		update(lc[node], i - 1, val, add);
	}
}

inline int query(int node, int i, int val){
	if(i == -1) return 0;
	if(val & (1 << i)){
		if((lc[node] != -1) and (leaves[lc[node]] > 0)) 
			return ((1 << i) | query(lc[node], i - 1, val));
		else if((rc[node] != -1) and (leaves[rc[node]] > 0))
			return (query(rc[node], i - 1, val));
		else return 0;
	}
	else{
		if((rc[node] != -1) and (leaves[rc[node]] > 0)) 
			return ((1 << i) | query(rc[node], i - 1, val));
		else if((lc[node] != -1) and (leaves[lc[node]] > 0))
			return (query(lc[node], i - 1, val));
		else return 0;	
	}
}


int main(){
	for(int i = 0; i < N * LN; i++){
		lc[i] = rc[i] = -1;
	}
	int q; scanf("%d", &q);
	char cmd[1]; int x;
	while(q--){
		scanf("%s %d", cmd, &x);
		if(cmd[0] == '+'){
			update(0, 30, x, 1);
		}
		else if(cmd[0] == '-'){
			update(0, 30, x, -1);
		}
		else{
			printf("%d\n", max(x, query(0, 30, x)));
		}
	}
	return 0;
}