Submission #494727

#	Time	Username	Problem	Language	Result	Execution time	Memory
494727		dannyboy20031204	DEL13 (info1cup18_del13)	C++17	0 / 100	68 ms	5016 KiB

del13

#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define mp make_pair 
using namespace std;
void db() {cout << endl;}
template <typename T, typename ...U> void db(T a, U ...b) {
    //return;
    cout << a << ' ', db(b...);
}
#ifdef Cloud
#define file freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout)
#else
#define file ios::sync_with_stdio(false); cin.tie(0)
#endif
const int N = 3001;
void solve(){
    int n, q;
    cin >> n >> q;
    bool stay[n + 1]{};
    for (int p, i = 0; i < q; i++) cin >> p, stay[p] = 1;
    set<pair<int, int>> s;
    for (int i = 1; i <= n; i++) s.insert({i, stay[i]});
    deque<int> ans;
    for (auto i : s){
        if (i.se == 0) {
            auto it = s.upper_bound(i);
            auto it2 = s.lower_bound(i);
            if (it == s.end() or it2 == s.begin()) continue;
            it2--;
            auto u = *it2, v = *it;
            if (u.se or v.se) continue;
            ans.push_back(i.fi);
            s.erase(u);
            s.erase(v);
        }
        else for (int t = 0; t < 2; t++){
            auto it = s.upper_bound(i);
            auto it2 = s.lower_bound(i);
            if (it == s.end() or it2 == s.begin()) continue;
            it2--;
            auto u = *it2, v = *it;
            if (u.se or v.se) continue;
            ans.push_back(i.fi);
            s.erase(u);
            s.erase(v);
        }
    }
    vector<int> v;
    for (auto i : s)
        if (i.se == 0)
            v.push_back(i.fi);
    if (!v.empty() and v.size() != 2) return void(cout << -1 << '\n');
    if (!v.empty() and v[0] != v[1] - 1) return void(cout << -1 << '\n');
    if (!v.empty() and (v[0] == 0 or stay[v[0] - 1])) return void(cout << -1 << '\n');
    if (!v.empty()) ans.push_front(v[0]);
    cout << ans.size() << '\n';
    for (int i : ans) cout << i << ' ';
    cout << '\n';
}
signed main(){
    file;
    int t;
    cin >> t;
    while (t--)
        solve();
}

• Subtask 1: 0 / 15
• Subtask 2: 0 / 15
• Subtask 3: 0 / 15
• Subtask 4: 0 / 25
• Subtask 5: 0 / 30