Submission #418153

#	Time	Username	Problem	Language	Result	Execution time	Memory
418153		2qbingxuan	Arranging Tickets (JOI17_arranging_tickets)	C++14	85 / 100	1068 ms	8740 KiB

arranging_tickets

#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#ifdef local
#define safe cerr<<__PRETTY_FUNCTION__<<" line "<<__LINE__<<" safe\n"
#define pary(a...) danb(#a, a)
#define debug(a...) qqbx(#a, a)
template <typename ...T> void qqbx(const char *s, T ...a) {
    int cnt = sizeof...(T);
    ((std::cerr << "\033[1;32m(" << s << ") = (") , ... , (std::cerr << a << (--cnt ? ", " : ")\033[0m\n")));
}
template <typename T> void danb(const char *s, T L, T R) {
    std::cerr << "\033[1;32m[ " << s << " ] = [ ";
    for (int f = 0; L != R; ++L)
        std::cerr << (f++ ? ", " : "") << *L;
    std::cerr << " ]\033[0m\n";
}
#else
#define debug(...) ((void)0)
#define safe ((void)0)
#define pary(...) ((void)0)
#endif // local
#define all(v) begin(v),end(v)
#define pb emplace_back
#define get_pos(u,x) int(lower_bound(all(u),x)-begin(u))

using namespace std;
using ll = int_fast64_t;
using ld = long double;
template <typename T> using min_heap = priority_queue<T, vector<T>, greater<T>>;
template <typename T> using max_heap = priority_queue<T, vector<T>, less<T>>;
const int inf = 1e9;
const int mod = 1000000007;
const ll INF = 1e18;
const int maxn = 5002;

#define int ll
signed main() {
    ios_base::sync_with_stdio(0), cin.tie(0);
    int n, m;
    cin >> n >> m;
    vector<pair<int,int>> seg;
    ll sum = 0;
    for (int i = 0; i < m; i++) {
        int l, r, c;
        cin >> l >> r >> c;
        if (l > r) swap(l, r);
        --l, --r;
        if (c % 2 == 1)
            seg.pb(l, r);
        sum += c / 2;
    }

    vector<int> pref(n);
    for (auto [l, r]: seg)
        pref[l] += 1, pref[r] -= 1;
    for (int i = 1; i < n; i++) pref[i] += pref[i-1];

    sort(all(seg));

    auto calc = [&](int x) {
        vector<int> need(n);
        for (int i = 0; i < n; i++)
            need[i] = max<ll>(0, (pref[i] - x + 1) / 2);
        int cnt = 0;
        max_heap<pair<int,int>> pq;
        min_heap<int> cover;
        for (int i = 0, it = 0; i < n; i++) {
            while (it < seg.size() && seg[it].first <= i) {
                auto [l, r] = seg[it];
                pq.emplace(r, it);
                it++;
            }
            while (cover.size() && cover.top() <= i) cover.pop();
            while (cover.size() < need[i]) {
                assert (!pq.empty());
                auto [r, id] = pq.top(); pq.pop();
                assert (r > i);
                cover.push(r);
                ++cnt;
            }
        }
        return x + cnt;
    };

    int p0 = 0;
    int p1 = 1;
    for (int s = 1 << 20; s > 1; s >>= 1) {
        if (calc(p0 + s - 2) > calc(p0 + s))
            p0 += s;
        if (calc(p1 + s - 2) > calc(p1 + s))
            p1 += s;
    }
    cout << sum + min(calc(p0), calc(p1)) << '\n';
}

Compilation message (stderr)

arranging_tickets.cpp: In function 'int main()':
arranging_tickets.cpp:54:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   54 |     for (auto [l, r]: seg)
      |               ^
arranging_tickets.cpp: In lambda function:
arranging_tickets.cpp:69:22: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   69 |                 auto [l, r] = seg[it];
      |                      ^
arranging_tickets.cpp:76:22: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   76 |                 auto [r, id] = pq.top(); pq.pop();
      |                      ^

• Subtask 1: 10 / 10
• Subtask 2: 35 / 35
• Subtask 3: 20 / 20
• Subtask 4: 20 / 20
• Subtask 5: 0 / 15