Submission #1240922

#	Time	Username	Problem	Language	Result	Execution time	Memory
1240922		trimkus	Fountain Parks (IOI21_parks)	C++20	55 / 100	304 ms	39024 KiB

parks

#include "parks.h"
#include <bits/stdc++.h>

using namespace std;

struct DSU {
    vector<int> e;
    DSU (int n) {
        e = vector<int>(n, -1);
    }
    int get(int x) {
        return e[x] < 0 ? x : e[x] = get(e[x]);
    }
    int size(int x) {
        return -e[get(x)];
    }
    bool unite(int x, int y) {
        x = get(x);
        y = get(y);
        if (x == y) return false;
        if (e[x] > e[y]) swap(x, y);
        e[x] += e[y];
        e[y] = x;
        return true;
    }
};


int construct_roads(std::vector<int> x, std::vector<int> y) {
    int N = x.size();
    const int MAXN = 2e5;
    vector<map<int, int>> mp(MAXN + 10);
    for (int i = 0; i < N; ++i) {
        mp[x[i]][y[i]] = i;
    }
    vector<array<int, 4>> edges;
    DSU dsu(N);
    for (int i = 0; i < N; ++i) {
        if (mp[x[i]].count(y[i] + 2)) {
            dsu.unite(i, mp[x[i]][y[i] + 2]);
            int j = mp[x[i]][y[i] + 2];
            int ny = y[i] + 1;
            int nx;
            if (((x[i] + y[i]) / 2) & 1) {
                nx = x[i] - 1;
            } else {
                nx = x[i] + 1;
            }
            edges.push_back({nx, ny, i, j});
        }
        if (mp[x[i] + 2].count(y[i])) {
            dsu.unite(i, mp[x[i] + 2][y[i]]);
            int j = mp[x[i] + 2][y[i]];
            int ny;
            int nx = x[i] + 1;
            if (((x[i] + y[i]) / 2) & 1) {
                ny = y[i] + 1;
            } else {
                ny = y[i] - 1;
            }
            edges.push_back({nx, ny, i, j});
        }
    }
    if (dsu.size(0) != N) return 0;
    sort(begin(edges), end(edges));
    vector<int> u, v, a, b;
    for (int it = 0; it < (int)edges.size(); ++it) {
        int i = edges[it][2];
        int j = edges[it][3];
        int x = edges[it][0];
        int y = edges[it][1];
        if (it > 0 && x == edges[it - 1][0] && y == edges[it - 1][1]) continue;
        u.push_back(i);
        v.push_back(j);
        a.push_back(x);
        b.push_back(y);
    }
    build(u, v, a, b);
    return 1;
}

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