Submission #952155

#	Time	Username	Problem	Language	Result	Execution time	Memory
952155		GrandTiger1729	Cake 3 (JOI19_cake3)	C++17	100 / 100	2377 ms	15184 KiB

cake3

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

const long long INF = 1e18;
int main()
{
    cin.tie(0)->sync_with_stdio(0);
    int n, K;
    cin >> n >> K;
    vector<pair<int, int>> a(n);
    for (int i = 0; i < n; i++)
    {
        cin >> a[i].second >> a[i].first;
    }
    sort(a.begin(), a.end());
    long long cur = 0;
    multiset<int> st, st2;
    auto add = [&](int x)
    {
        st.insert(x);
        cur += x;
        while (st.size() > K)
        {
            auto it = st.begin();
            cur -= *it;
            st2.insert(*it);
            st.erase(it);
        }
    };
    auto del = [&](int x)
    {
        auto it = st.find(x);
        if (it == st.end())
        {
            it = st2.find(x);
            st2.erase(it);
        }
        else
        {
            cur -= *it;
            st.erase(it);
            while (st2.size() && st.size() < K)
            {
                it = --st2.end();
                cur += *it;
                st.insert(*it);
                st2.erase(it);
            }
        }
    };
    int ll = 0, rr = -1;
    auto query = [&]() -> long long
    {
        return st.size() == K ? cur : -INF;
    };
    long long ans = -INF;
    function<void(int, int, int, int)> solve = [&](int l, int r, int ql, int qr)
    {
        if (l > r)
        {
            return;
        }
        int mid = (l + r) / 2;
        pair<long long, int> maxn(-INF, INF);
        while (rr < mid)
        {
            add(a[++rr].second);
        }
        while (ll > qr)
        {
            add(a[--ll].second);
        }
        while (rr > mid && rr >= ll)
        {
            del(a[rr--].second);
        }
        if (rr > mid && rr < ll)
        {
            rr = mid;
            ll = mid + 1;
        }
        while (ll <= qr && ll <= rr)
        {
            del(a[ll++].second);
        }
        while (ll > ql)
        {
            add(a[--ll].second);
            maxn = max(maxn, make_pair(query() - 2ll * (a[mid].first - a[ll].first), ll));
        }
        auto [mx, j] = maxn;
        ans = max(ans, mx);
        solve(l, mid - 1, ql, j);
        solve(mid + 1, r, j, qr);
    };
    solve(K - 1, n - 1, 0, n - 1);
    cout << ans << '\n';
    return 0;
}

Compilation message (stderr)

cake3.cpp: In lambda function:
cake3.cpp:22:26: warning: comparison of integer expressions of different signedness: 'std::multiset<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   22 |         while (st.size() > K)
      |                ~~~~~~~~~~^~~
cake3.cpp: In lambda function:
cake3.cpp:42:44: warning: comparison of integer expressions of different signedness: 'std::multiset<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   42 |             while (st2.size() && st.size() < K)
      |                                  ~~~~~~~~~~^~~
cake3.cpp: In lambda function:
cake3.cpp:54:26: warning: comparison of integer expressions of different signedness: 'std::multiset<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   54 |         return st.size() == K ? cur : -INF;
      |                ~~~~~~~~~~^~~~

• Subtask 1: 5 / 5
• Subtask 2: 19 / 19
• Subtask 3: 76 / 76