Submission #1240699

#	Time	Username	Problem	Language	Result	Execution time	Memory
1240699		trimkus	Fountain Parks (IOI21_parks)	C++20	0 / 100	3596 ms	5308 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]);
    }
    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) {
    if (x.size() == 1) {
	    build({}, {}, {}, {});
        return 1;
    }
    vector<array<int, 3>> st;
    int N = x.size();
    for (int i = 0; i < N; ++i) {
        st.push_back({y[i], x[i], i});
    }
    sort(begin(st), end(st));
    vector<array<int, 2>> con;
    for (int i = 1; i < N; ++i) {
        if (st[i][0] == st[i - 1][0] && st[i][1] - st[i - 1][1] == 2) {
            con.push_back({st[i][2], st[i - 1][2]});
        }
    }
    DSU dsu(N);
    for (auto& [i, j] : con) {
        dsu.unite(i, j);
    }
    st.clear();
    for (int i = 0; i < N; ++i) {
        st.push_back({x[i], y[i], i});
    }
    sort(begin(st), end(st));
    vector<array<int, 2>> ncon;
    for (int i = 1; i < N; ++i) {
        if (st[i][0] == st[i - 1][0] && st[i][1] - st[i - 1][1] == 2) {
            ncon.push_back({st[i][2], st[i - 1][2]});
        }
    }
    sort(begin(ncon), end(ncon), [&](array<int, 2> a, array<int, 2> b) {
        int nx = x[a[0]];
        int nx1 = x[b[0]];
        if (nx == 2 || nx == 6) return true;
        return nx < nx1;
    });
    vector<bool> keep(ncon.size());
    for (int it = 0; it < ncon.size(); ++it) {
        int i = ncon[it][0];
        int j = ncon[it][1];
        keep[it] = dsu.unite(i, j);
    }
    vector<array<int, 2>> tmp;
    for (int it = 0; it < ncon.size(); ++it) {
        if (keep[it]) tmp.push_back(ncon[it]);
    }
    ncon = tmp;
    for (auto& [i, j] : ncon) {
        con.push_back({i, j});
    }
    if (-dsu.e[dsu.get(0)] != N) return 0;
    vector<int> v, u, a, b;
    set<array<int, 2>> vis;
    for (auto& [i, j] : con) {
        if (y[i] == y[j]) {
            int nx = min(x[i], x[j]) + 1;
            int ny;
            if (nx == 3) {
                ny = y[i] - 1;
            } else {
                assert(nx == 5);
                ny = y[i] + 1;
            }
            vis.insert({nx, ny});
            v.push_back(i);
            u.push_back(j);
            a.push_back(nx);
            b.push_back(ny);
        } else {
            int nx, ny;
            assert(x[i] == x[j]);
            ny = min(y[i], y[j]) + 1;
            if (x[i] == 2) {
                nx = x[i] - 1;
            } else if (x[i] == 6) {
                nx = x[i] + 1;
            } else {
                assert(x[i] == 4);
                nx = x[i] - 1;
                if (vis.count({nx, ny})) {
                    nx = x[i] + 1;
                }
            }
            assert(!vis.count({nx, ny}));
            vis.insert({nx, ny});
            v.push_back(i);
            u.push_back(j);
            a.push_back(nx);
            b.push_back(ny);
        }
    }
    build(u, v, a, b);
    return 1;
}

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