Submission #749710

#	Time	Username	Problem	Language	Result	Execution time	Memory
749710		finn__	Teams (CEOI11_tea)	C++17	100 / 100	2212 ms	45904 KiB

tea

#pragma GCC optimize("O3")
#pragma GCC target("avx2")

#include <bits/stdc++.h>
using namespace std;

template <typename T, size_t L>
struct max_segment_tree
{
    T tree[2 * L];

    void update(size_t i, T x)
    {
        tree[i += L] = x;
        while (i >>= 1)
            tree[i] = max(tree[i << 1], tree[(i << 1) | 1]);
    }

    T range_max(size_t i, size_t j)
    {
        i += L, j += L;
        T x = T();
        while (i <= j)
        {
            if (i & 1)
                x = max(x, tree[i++]);
            if (!(j & 1))
                x = max(x, tree[j--]);
            i >>= 1;
            j >>= 1;
        }
        return x;
    }
};

constexpr size_t N = 1000001, L = 1 << 20;

size_t n;
pair<int, int> a[N];
int pre[N];
max_segment_tree<int, L> tree1;
max_segment_tree<pair<int, int>, L> tree2;

int max_number_of_teams(size_t max_team_size)
{
    memset(tree1.tree, 0, sizeof tree1.tree);
    for (size_t i = 1; i <= n; ++i)
        if (i >= a[i].first)
        {
            size_t u = i - min(max_team_size, i), v = i - a[i].first;
            int x = tree1.range_max(u, v);
            if (u && !x)
            {
                if (i == n)
                    return 0;
                continue;
            }
            if (i == n)
                return x + 1;
            tree1.update(i, x + 1);
        }
}

void find_predecessor_array(size_t max_team_size)
{
    for (size_t i = 1; i <= n; ++i)
        if (i >= a[i].first)
        {
            size_t u = i - min(max_team_size, i), v = i - a[i].first;
            auto x = tree2.range_max(u, v);
            if (u && !x.first)
                continue;
            pre[i] = x.second;
            tree2.update(i, pair<int, int>(x.first + 1, i));
        }
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n;
    for (size_t i = 1; i <= n; ++i)
        cin >> a[i].first, a[i].second = i;
    sort(a + 1, a + n + 1);

    int t = max_number_of_teams(n);
    cout << t << '\n';
    size_t u = a[n].first, v = n;
    while (u < v)
    {
        size_t mid = (u + v) / 2;
        if (max_number_of_teams(mid) == t)
            v = mid;
        else
            u = mid + 1;
    }

    find_predecessor_array(u);
    int i = n;
    while (i)
    {
        vector<int> team;
        for (int j = pre[i] + 1; j <= i; ++j)
            team.push_back(a[j].second);
        i = pre[i];
        cout << team.size() << ' ';
        for (int const &x : team)
            cout << x << ' ';
        cout << '\n';
    }
}

Compilation message (stderr)

tea.cpp: In function 'int max_number_of_teams(size_t)':
tea.cpp:48:15: warning: comparison of integer expressions of different signedness: 'size_t' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   48 |         if (i >= a[i].first)
      |             ~~^~~~~~~~~~~~~
tea.cpp: In function 'void find_predecessor_array(size_t)':
tea.cpp:67:15: warning: comparison of integer expressions of different signedness: 'size_t' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   67 |         if (i >= a[i].first)
      |             ~~^~~~~~~~~~~~~
tea.cpp: In function 'int max_number_of_teams(size_t)':
tea.cpp:62:1: warning: control reaches end of non-void function [-Wreturn-type]
   62 | }
      | ^

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10