Submission #1134040

#	Time	Username	Problem	Language	Result	Execution time	Memory
1134040		alterio	Fountain Parks (IOI21_parks)	C++20	15 / 100	95 ms	20904 KiB

parks

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

using namespace std;

#define all(x) (x).begin(), (x).end()

const int mxn = 2e5 + 100;

int ldr[mxn], rnk[mxn];

int Find(int x) {
    if (ldr[x] == x) return x;
    return ldr[x] = Find(ldr[x]);
}

void Union(int x, int y) {
    x = Find(x), y = Find(y);
    if (x == y) return;
    if (rnk[y] > rnk[x]) swap(x, y);
    rnk[x] += rnk[y];
    ldr[y] = x;
}

int construct_roads(vector<int> x, vector<int> y) {
    int n = x.size();
    if (x.size() == 1) {
        build({}, {}, {}, {});
        return 1;
    }
    for (int i = 0; i < mxn; i++) ldr[i] = i, rnk[i] = 1;

    vector<int> u, v, a, b;
    vector<pair<int, int>> V1, V2;
    for (int i = 0; i < n; i++) {
        if (x[i] == 2) V1.push_back({y[i], i});
        else V2.push_back({y[i], i});
    }
    sort(all(V1));
    sort(all(V2));
    for (int i = 0; i < n; i++) {
        if (i + 1 < V1.size() && V1[i + 1].first - V1[i].first == 2) {
            Union(V1[i].second, V1[i + 1].second);
            u.push_back(V1[i].second);
            v.push_back(V1[i + 1].second);
            a.push_back(1);
            b.push_back(V1[i].first + 1);
        }
        if (i + 1 < V2.size() && V2[i + 1].first - V2[i].first == 2) {
            Union(V2[i].second, V2[i + 1].second);
            u.push_back(V2[i].second);
            v.push_back(V2[i + 1].second);
            a.push_back(5);
            b.push_back(V2[i].first + 1);
        }
    }

    int l = 0, r = 0;
    while (l < V1.size() && r < V2.size()) {
        if (V1[l].first < V2[r].first) {
            l++;
            continue;
        }
        if (V2[r].first < V1[l].first) {
            r++;
            continue;
        }
        Union(V1[l].second, V2[r].second);
        u.push_back(V1[l].second);
        v.push_back(V2[r].second);
        a.push_back(3);
        b.push_back(V1[l].first + 1);
        l++;
        r++;
    }

    set<int> s;
    for (int i = 0; i < n; i++) s.insert(Find(i));
    if (s.size() != 1) return 0;

    build(u, v, a, b);
    return 1;
}

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