Submission #707347

#	Time	Username	Problem	Language	Result	Execution time	Memory
707347		Stickfish	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	57 / 100	1085 ms	124856 KiB

skyscraper

#include <iostream>
#include <vector>
#include <set>
#include <algorithm>
#include <bitset>
using namespace std;

const int MAXN = 30100;
const int SQN = 200;
const int INF = 1e9 + 177013;
pair<int, int> dogs[MAXN];
vector<int> jlen[MAXN];

struct modmin {
    void resize(int n) {
        sz = n;
        for (int i = 0; i < n; ++i)
            active.insert(i);
        pivots = {{-INF, 10}, {INF, 10}};
    }

    void insert_pivot(int x, int vl) {
        auto it = active.lower_bound(x);
        if (it != active.end())
            best.erase({get_value(*it), *it});
        if (it != active.begin())
            best.erase({get_value(*prev(it)), *prev(it)});
        pivots.insert(lower_bound(pivots.begin(), pivots.end(), pair<int, int>{x, -1}), {x, vl});
        if (it != active.end())
            best.insert({get_value(*it), *it});
        if (it != active.begin())
            best.insert({get_value(*prev(it)), *prev(it)});
    }

    void deactivate(int x) {
        int vl = get_value(x);
        auto it = active.find(x);
        if (best.find({vl, x}) != best.end()) {
            best.erase({vl, x});
            if (next(it) != active.end())
                best.insert({get_value(*next(it)), *next(it)});
            if (it != active.begin())
                best.insert({get_value(*prev(it)), *prev(it)});
        }
        active.erase(it);
    }

    pair<int, int> get_min() {
        if (best.empty())
            return {INF, INF};
        return *best.begin();
    }
 private:
     int sz;
     set<pair<int, int>> pivots;
     set<int> active;
     set<pair<int, int>> best;

     int get_value(int x) {
         auto it = pivots.lower_bound({x, -1});
         return min(get_transit(it, x), get_transit(prev(it), x));
     }

     int get_transit(set<pair<int, int>>::iterator it, int x) {
         return abs(x - it->first) + it->second;
     }
};

bitset<MAXN> used;
int dist_long[MAXN];
modmin dist_short[SQN][SQN];

signed main() {
    int n, m;
    cin >> n >> m;
    for (int i = 0; i < m; ++i) {
        cin >> dogs[i].first >> dogs[i].second;
        jlen[dogs[i].first].push_back(dogs[i].second);
    }
    int s = dogs[0].first;
    int t = dogs[1].first;
    for (int i = 0; i < n; ++i)
        dist_long[i] = INF;
    dist_long[s] = 0;
    for (int d = 1; d < SQN; ++d) {
        for (int md = 0; md < n && md < d; ++md) {
            dist_short[d][md].resize((n - md - 1) / d + 1);
        }
    }
    set<pair<int, int>> rdist_short;
    int T = n;
    while (T--) {
        //cout << "A" << endl;
        pair<int, int> opt = {INF, INF};
        for (int i = 0; i < n; ++i) {
            if (!used[i])
                opt = min(opt, {dist_long[i], i});
        }
        if (rdist_short.size()) {
            opt = min(opt, *rdist_short.begin());
        }
        auto [dist, v] = opt;
        if (dist >= INF)
            break;
        dist_long[v] = dist;
        used[v] = 1;
        for (int d = 1; d < SQN; ++d) {
            int md = v % d;
            pair<int, int> cval = dist_short[d][md].get_min();
            cval.second = md + d * cval.second;
            rdist_short.erase(cval);

            dist_short[d][md].deactivate(v / d);

            pair<int, int> ncval = dist_short[d][md].get_min();
            ncval.second = md + d * ncval.second;
            rdist_short.insert(ncval);
        }
        for (auto p : jlen[v]) {
            if (p >= SQN) {
                for (int k = 1; p * k <= v; ++k)
                    dist_long[v - p * k] = min(dist_long[v - p * k], dist + k);
                for (int k = 1; v + p * k < n; ++k)
                    dist_long[v + p * k] = min(dist_long[v + p * k], dist + k);
            } else {
                int md = v % p;
                pair<int, int> cval = dist_short[p][md].get_min();
                cval.second = md + p * cval.second;
                rdist_short.erase(cval);

                dist_short[p][md].insert_pivot(v / p, dist);

                pair<int, int> ncval = dist_short[p][md].get_min();
                ncval.second = md + p * ncval.second;
                rdist_short.insert(ncval);
            }
        }
    }
    if (dist_long[t] >= INF)
        cout << "-1\n";
    else
        cout << dist_long[t] << '\n';
}

• Subtask 1: 10 / 10
• Subtask 2: 12 / 12
• Subtask 3: 14 / 14
• Subtask 4: 21 / 21
• Subtask 5: 0 / 43