Submission #443471

#	Time	Username	Problem	Language	Result	Execution time	Memory
443471		mjhmjh1104	Fountain Parks (IOI21_parks)	C++17	30 / 100	673 ms	40940 KiB

parks

#include "parks.h"
#include <map>
#include <set>
#include <cstdio>
#include <vector>
#include <utility>
#include <algorithm>
using namespace std;

int uf[200006];

int _find(int x) {
    if (uf[x] == -1) return x;
    return uf[x] = _find(uf[x]);
}

void _merge(int x, int y) {
    x = _find(x), y = _find(y);
    if (x != y) uf[x] = y;
}

map<pair<int, int>, int> m;
set<pair<int, int>> s;

int construct_roads(vector<int> x, vector<int> y) {
    if ((int)x.size() == 1) return build({}, {}, {}, {}), 1;
    int n = (int)x.size();
    for (int i = 0; i < n; i++) uf[i] = -1;
    vector<int> u, v, a, b;
    vector<pair<int, int>> edges, n_edges;
    vector<int> points;
    for (int i = 0; i < n; i++) m[{ x[i], y[i] }] = i;
    for (int i = 0; i < n; i++) if (m.count({ x[i], y[i] - 2 })) {
        edges.push_back({ m[{ x[i], y[i] - 2 }], i });
        _merge(edges.back().first, edges.back().second);
    }
    for (int i = 0; i < n; i++) /*if (!m.count({ x[i], y[i] - 2 }) || !m.count({ x[i], y[i] + 2 }))*/ points.push_back(i);
    sort(points.begin(), points.end(), [&](const int &a, const int &b) {
        if (y[a] != y[b]) return y[a] < y[b];
        return x[a] < x[b];
    });
    for (int t = 0; t < (int)points.size(); t++) {
        int i = points[t];
        if (m.count({ x[i] - 2, y[i] })) {
            int t = m[{ x[i] - 2, y[i] }];
            if (_find(t) != _find(i)) {
                edges.push_back({ t, i });
                _merge(t, i);
            }
        }
        if (m.count({ x[i] + 2, y[i] })) {
            int t = m[{ x[i] + 2, y[i] }];
            if (_find(t) != _find(i)) {
                edges.push_back({ t, i });
                _merge(t, i);
            }
        }
    }
    for (int i = 1; i < n; i++) if (_find(0) != _find(i)) return 0;
    //int min_x = *min_element(x.begin(), x.end()), max_x = *max_element(x.begin(), x.end());
    for (auto &i: edges) {
        /*if (x[i.first] == x[i.second]) {
            u.push_back(i.first);
            v.push_back(i.second);
            a.push_back(x[i.first] - 1);
            b.push_back((y[i.first] + y[i.second]) / 2);
            s.insert({ a.back(), b.back() });
        } else*/ n_edges.push_back(i);
    }
    sort(n_edges.begin(), n_edges.end(), [&](const pair<int, int> &a, const pair<int, int> &b) {
        if (x[a.first] + x[a.second] != x[b.first] + x[b.second]) return x[a.first] + x[a.second] < x[b.first] + x[b.second];
        return y[a.first] + y[a.second] < y[b.first] + y[b.second];
    });
    for (auto &i: n_edges) {
        if (x[i.first] == x[i.second]) {
            if (!s.count({ x[i.first] - 1, (y[i.first] + y[i.second]) / 2 })) {
                s.insert({ x[i.first] - 1, (y[i.first] + y[i.second]) / 2 });
                u.push_back(i.first);
                v.push_back(i.second);
                a.push_back(x[i.first] - 1);
                b.push_back((y[i.first] + y[i.second]) / 2);
            } else {
                if (s.count({ x[i.first] + 1, (y[i.first] + y[i.second]) / 2 })) return 0;
                s.insert({ x[i.first] + 1, (y[i.first] + y[i.second]) / 2 });
                u.push_back(i.first);
                v.push_back(i.second);
                a.push_back(x[i.first] + 1);
                b.push_back((y[i.first] + y[i.second]) / 2);
            }
        } else {
            if (!s.count({ (x[i.first] + x[i.second]) / 2, y[i.first] - 1 })) {
                s.insert({ (x[i.first] + x[i.second]) / 2, y[i.first] - 1 });
                u.push_back(i.first);
                v.push_back(i.second);
                a.push_back((x[i.first] + x[i.second]) / 2);
                b.push_back(y[i.first] - 1);
            } else {
                if (s.count({ (x[i.first] + x[i.second]) / 2, y[i.first] + 1 })) return 0;
                s.insert({ (x[i.first] + x[i.second]) / 2, y[i.first] + 1 });
                u.push_back(i.first);
                v.push_back(i.second);
                a.push_back((x[i.first] + x[i.second]) / 2);
                b.push_back(y[i.first] + 1);
            }
        }
    }
    build(u, v, a, b);
    return 1;
}

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 15 / 15
• Subtask 4: 0 / 20
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30