/*
* @uni_kakurenbo
* https://github.com/uni-kakurenbo/competitive-programming-workspace
*
* CC0 1.0 http://creativecommons.org/publicdomain/zero/1.0/deed.ja
*/
/* #language C++ 20 GCC */
#define PROBLEM "https://judge.yosupo.jp/problem/predecessor_problem"
#include "sneaky/enforce_int128_enable.hpp"
#include <iostream><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include "snippet/aliases.hpp"
#include "snippet/fast_io.hpp"
#include "snippet/iterations.hpp"
#include "adaptor/io.hpp"
#include "adaptor/valarray.hpp"
#include "data_structure/fenwick_tree.hpp"
#include "data_structure/dynamic_set.hpp"
signed main() {
uni::i32 n, q; input >> n >> q;
uni::dynamic_set<uni::i32, uni::treap_context<uni::i32>> st;
REP(i, n) {
char v; input >> v;
if(v == '1') st.insert(i);
}
REP(q) {
uni::i32 t; input >> t;
if(t == 0) {
uni::i32 k; input >> k;
st.insert<true>(k);
}
if(t == 1) {
uni::i32 k; input >> k;
st.erase(k);
}
if(t == 2) {
uni::i32 k; input >> k;
print(st.contains(k));
}
if(t == 3) {
uni::i32 k; input >> k;
auto itr = st.lower_bound(k);
print(itr == st.end() ? -1 : *itr);
}
if(t == 4) {
uni::i32 k; input >> k;
auto itr = st.upper_bound(k);
print(itr == st.begin() ? -1 : *std::ranges::prev(itr));
}
// debug(st);
// st.dump_rich();
}
}