2025-09-12 14:50:25 -03:00

172 lines
3.7 KiB
C++

/* Problem URL: https://codeforces.com/contest/2093/problem/G */
#include <bits/stdc++.h>
using namespace std;
#define V vector
#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)
#define rep(i, lim) for (size_t i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (size_t i = s; i < (lim); i++)
#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;
template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
os << vec[0];
for (size_t i = 1; i < vec.size(); i++) {
os << ' ' << vec[i];
}
os << '\n';
return os;
}
template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
for (auto &i : vec) {
is >> i;
}
return is;
}
template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
for (auto &i : vec) {
os << i[0];
for (size_t j = 1; j < i.size(); j++) { os << ' ' << i[j];
}
os << '\n';
}
return os;
}
template<class v>
auto operator>>(istream &is, vector<vector<v>> &vec)->istream& {
for (auto &i : vec) {
for (auto &j : i) {
is >> j;
}
}
return is;
}
struct node {
int nodes[2], count[2];
node(): count(0) {
fill(nodes, nodes + 2, 0);
}
int& operator[](int i) {
return nodes[i];
}
};
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
int t;
cin >> t;
while (t--) {
int n, k;
cin >> n >> k;
vi array(n);
cin >> array;
V<node> bits(1);
auto add = [&](int i){
int now = 0;
for (int j = 30; j >= 0; j--) {
int bit = (i >> j) & 1;
if (bits[now][bit] == 0) {
bits[now][bit] = bits.size();
bits.emplace_back();
}
bits[now].count[bit]++;
now = bits[now][bit];
}
};
auto rem = [&](int i){
int now = 0;
for (int j = 30; j >= 0; j--) {
int bit = (i >> j) & 1;
bits[now].count[bit]--;
if (bits[now].count[bit] == 0) {
bits[now][bit] = 0;
return;
}
now = bits[now][bit];
}
};
auto search = [&](int i){
int now = 0;
for (int j = 30; j >= 0; j--) {
int bit = (i >> j) & 1;
if (bits[now][!bit] == 0) {
if (((k >> j) & 1) == 1) {
return false;
}
now = bits[now][bit];
continue;
}
if (((k >> j) & 1) == 0) {
return true;
}
now = bits[now][!bit];
}
return true;
};
int ans = INT32_MAX;
int l = 0, r = 0;
add(array[0]);
while (r < array.size() && l <= r) {
if (search(array[r])) {
rmin(ans, r - l + 1);
rem(array[l]);
l++;
continue;
}
r++;
if (r < array.size()) {
add(array[r]);
}
}
if (r == array.size() && search(array[l])) {
rmin(ans, r - l + 1);
}
cout << (ans == INT32_MAX ? -1 : ans) << '\n';
}
}