Submission #494731

#	Time	Username	Problem	Language	Result	Execution time	Memory
494731		dannyboy20031204	DEL13 (info1cup18_del13)	C++17	15 / 100	65 ms	5388 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]{}, last[n + 1]{};
    for (int p, i = 0; i < q; i++) cin >> p, stay[p] = 1;
    bool find = 0;
    for (int i = n; i >= 0; i--){
        if (stay[i]) continue;
        if (!find) last[i] = 1, find = 1;
        else last[i] |= last[i + 1]; 
    }
    set<pair<int, int>> s;
    for (int i = 1; i <= n; i++) s.insert({i, stay[i]});
    while (!s.empty() and (*(--s.end())).se) s.erase(--s.end());
    deque<int> ans;
    vector<int> v;
    for (auto i : s){
        if (last[i.fi]) v.push_back(i.fi);
        else 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);
        }
    }
    for (auto i : s) if (i.se == 0 and !last[i.fi]) return void(cout << -1 << '\n');
    if (!v.empty() and (v.size() % 2 or v[0] == 1)) return void(cout << -1 << '\n');
    if (!v.empty() and stay[v[0] - 1]) return void(cout << -1 << '\n');
    if (!v.empty()) for (int i = 0; i < v.size(); i += 2) ans.push_front(v[i]);
    cout << ans.size() << '\n';
    for (int i : ans) cout << i << ' ';
    cout << '\n';
}
signed main(){
    file;
    int t;
    cin >> t;
    while (t--)
        solve();
}

Compilation message (stderr)

del13.cpp: In function 'void solve()':
del13.cpp:62:39: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   62 |     if (!v.empty()) for (int i = 0; i < v.size(); i += 2) ans.push_front(v[i]);
      |                                     ~~^~~~~~~~~~

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