Submission #1100808

#	Time	Username	Problem	Language	Result	Execution time	Memory
1100808		Kirill22	DEL13 (info1cup18_del13)	C++17	100 / 100	15 ms	6432 KiB

del13

#include "bits/stdc++.h"

using namespace std;

//#include "debug.h"

mt19937 gen(22);

void solve() {
    int n, m;
    cin >> n >> m;
    vector<int> a(n), ord;
    for (int i = 0; i < m; i++) {
        int x;
        cin >> x;
        x--;
        ord.push_back(x);
        a[x] = 1;
    }
    if (!m || (n - m) % 2) {
        cout << -1 << '\n';
        return;
    }
    std::sort(ord.begin(), ord.end());
    ord.push_back(n);
    vector<map<int, int>> dp(m + 1);
    if (ord[0] % 2 == 1) {
        dp[0][1] = -1;
    } else if (!ord[0]) {
        dp[0][0] = -1;
    } else {
        dp[0][2] = -1;
    }
    for (int i = 1; i <= m; i++) {
        int len = ord[i] - ord[i - 1] - 1;
        for (auto [v, _] : dp[i - 1]) {
            if (len < v) {
                continue;
            }
            if ((len - v) % 2 == 1) {
                dp[i][1] = v;
            } else if (len == v) {
                dp[i][0] = v;
            } else if (v) {
                dp[i][0] = v;
                dp[i][2] = v;
            } else {
                dp[i][2] = v;
            }
        }
    }
//    debug(dp);
    if (dp[m].find(0) == dp[m].end()) {
        cout << -1 << '\n';
        return;
    }
    vector<int> ans, ans2, tmp, used(n), kek(n);
    {
        int j = 0;
        for (int i = m - 1; i >= 0; i--) {
            j = dp[i + 1][j];
            kek[ord[i]] = j;
        }
    }
//    debug(kek);
    for (int i = 0; i < n; ) {
        if (a[i] == 1) {
            i++;
            continue;
        }
        int j = i;
        while (j < n && a[j] == 0) {
            j++;
        }
        int rem = 0;
        if (i && a[i - 1] == 1) {
            rem += kek[i - 1];
        }
        if (j < n && a[j] == 1) {
            rem += kek[j];
        }
//        debug(rem);
        if (j - i < rem) {
            cout << -1 << '\n';
            return;
        }
        for (int v = i; v < j; v++) {
            tmp.push_back(v);
        }
        while ((int) tmp.size() > rem) {
            if ((int) tmp.size() < 3) {
                cout << -1 << '\n';
                return;
            }
            ans.push_back(tmp.end()[-2]);
            used[tmp.end()[-1]] = used[tmp.end()[-3]] = 1;
            tmp.pop_back();
            tmp.pop_back();
            tmp.pop_back();
            tmp.push_back(ans.back());
        }
        tmp.clear();
        i = j;
    }
    int want = 0;
    for (int i = 0; i < n; i++) {
        if (used[i]) {
            continue;
        }
        if (a[i] == 1) {
            if (want) {
                cout << -1 << '\n';
                return;
            }
            want = (int) tmp.size();
            tmp.clear();
            for (int j = 0; j < want; j++) {
                ans.push_back(i);
            }
        } else {
            if (want) {
                want--;
            } else {
                tmp.push_back(i);
            }
        }
    }
    if (!tmp.empty() || want) {
        cout << -1 << '\n';
        return;
    }
    cout << (int) ans.size() << '\n';
    for (auto& i : ans) {
        cout << i + 1 << " ";
    }
    cout << '\n';
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int t = 1;
    cin >> t;
    while (t--) {
        solve();
    }
}

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