Submission #1240523

#	Time	Username	Problem	Language	Result	Execution time	Memory
1240523		trimkus	Fountain Parks (IOI21_parks)	C++20	0 / 100	0 ms	328 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]);
    }
    void unite(int x, int y) {
        x = get(x);
        y = get(y);
        if (x == y) return;
        if (e[x] > e[y]) swap(x, y);
        e[x] += e[y];
        e[y] = x;
    }
};

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({x[i], y[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]});
        }
    }
    st.clear();
    for (int i = 0; i < N; ++i) {
        st.push_back({y[i], x[i], i});
    }
    sort(begin(st), end(st));
    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]});
        }
    }
    for (int i = 0; i < N; ++i) {
        if (con[i][0] > con[i][1]) swap(con[i][0], con[i][1]);
    }
    sort(begin(con), end(con));
    con.erase(unique(begin(con), end(con)), end(con));
    DSU dsu(N);
    for (auto& [x, y] : con) {
        dsu.unite(x, y);
    }
    if (-dsu.e[dsu.get(0)] != N) return 0;
    vector<int> v, u, a, b;
    for (auto& [i, j] : con) {
        v.push_back(i);
        u.push_back(j);
        if (x[i] == x[j]) {
            int ny = min(y[i], y[j]) + 1;
            b.push_back(ny);
            if (x[i] == 2) {
                a.push_back(x[i] - 1);
            } else {
                a.push_back(x[i] + 1);
            }
        } else {
            assert(y[i] == y[j]);
            int nx = min(x[i], x[j]) + 1;
            a.push_back(nx);
            b.push_back(y[i] + 1);
        }
    }
    build(v, u, 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