Submission #588151

#	Time	Username	Problem	Language	Result	Execution time	Memory
588151		Clan328	Fountain Parks (IOI21_parks)	C++17	30 / 100	214 ms	33488 KiB

parks

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

using namespace std;

#define pb push_back

struct Coord {
    int x, y, i;

    bool operator<(Coord other) const  {
        if (y == other.y) {
            return x < other.x;
        }
        return y < other.y;
    }
};

int n;
vector<Coord> coords;
std::vector<int> u, v, a, b;

vector<int> link;

int find(int x) {
    if (link[x] != x) link[x] = find(link[x]);
    return link[x];
}

void unite(int a, int b) {
    int x = find(a), y = find(b);
    link[x] = y;
}

bool same(int a, int b) {
    return find(a) == find(b);
}

void connect(int i, int j) {
    if (coords[i].x == coords[j].x) {
        u.pb(coords[i].i);
        v.pb(coords[j].i);
        if (coords[i].x == 4)
            a.pb(coords[i].x+1);
        else
            a.pb(coords[i].x-1);
        b.pb(coords[i].y+1);
    } else if (coords[i].y == coords[j].y) {
        u.pb(coords[i].i);
        v.pb(coords[j].i);
        a.pb(coords[i].x+1);
        b.pb(coords[i].y-1);
    }
}

int construct_roads(std::vector<int> x, std::vector<int> y) {
    if (x.size() == 1) {
        build({}, {}, {}, {});
        return 1;
    }  

    n = x.size();

    int maxX = 0;
    for (int i = 0; i < n; i++) maxX = max(maxX, x[i]);

    bool res = true;
    if (maxX <= 4) {
        coords = vector<Coord>(n);
        for (int i = 0; i < n; i++) {
            coords[i] = {x[i], y[i], i};
        }

        sort(coords.begin(), coords.end());
        
        link = vector<int>(n);
        iota(link.begin(), link.end(), 0);
        for (int i = 0; i < n-1; i++) {
            if ((coords[i].y+2 == coords[i+1].y && coords[i].x == coords[i+1].x) || (coords[i].y == coords[i+1].y && abs(coords[i+1].x-coords[i].x) == 2)) {
                connect(i, i+1);
                unite(i, i+1);
            }
            if (i+2 < n && ((coords[i].y+2 == coords[i+2].y && coords[i].x == coords[i+2].x) || (coords[i].y == coords[i+2].y && abs(coords[i+2].x-coords[i].x) == 2))) {
                connect(i, i+2);
                unite(i, i+2);
            }
        }
        
        for (int i = 0; i < n-1; i++) {
            res &= find(i) == find(i+1);
        }
    } else {
        int maxY = 0;
        for (int i = 0; i < n; i++) maxY = max(maxY, y[i]);

        link = vector<int>(n);
        iota(link.begin(), link.end(), 0);
        vector<vector<int>> mat(maxY/2, vector<int>(3)), matIdx(maxY/2, vector<int>(3));
        for (int i = 0; i < n; i++) {
            mat[y[i]/2-1][x[i]/2-1] = 1;
            matIdx[y[i]/2-1][x[i]/2-1] = i;
        }

        map<int, map<int, int>> bench;

        for (int i = 0; i < maxY/2; i++) {
            if (mat[i][0] && mat[i][1]) {
                if (bench[3][2*i+1]) {
                    if (!same(matIdx[i][0], matIdx[i][1])) {
                        if (bench[3][2*i+3]) res = false;
                        u.pb(matIdx[i][0]);
                        v.pb(matIdx[i][1]);
                        a.pb(3);
                        b.pb(2*i+3);
                        unite(matIdx[i][0], matIdx[i][1]);
                    }
                } else {
                    u.pb(matIdx[i][0]);
                    v.pb(matIdx[i][1]);
                    a.pb(3);
                    b.pb(2*i+1);
                    unite(matIdx[i][0], matIdx[i][1]);
                }
                if (a.size()) {
                    bench[a[a.size()-1]][b[b.size()-1]] = true;
                }
            }
            if (mat[i][1] && mat[i][2]) {
                if (bench[5][2*i+1]) {
                    if (!same(matIdx[i][1], matIdx[i][2])) {
                        if (bench[5][2*i+3]) res = false;
                        u.pb(matIdx[i][1]);
                        v.pb(matIdx[i][2]);
                        a.pb(5);
                        b.pb(2*i+3);
                        unite(matIdx[i][1], matIdx[i][2]);
                    }
                } else {
                    u.pb(matIdx[i][1]);
                    v.pb(matIdx[i][2]);
                    a.pb(5);
                    b.pb(2*i+1);
                    unite(matIdx[i][1], matIdx[i][2]);
                }
                if (a.size()) {
                    bench[a[a.size()-1]][b[b.size()-1]] = true;
                }
            }
            if (i == maxY/2-1) continue;
            bool isValid = false;
            if (mat[i][0] && mat[i+1][0]) {
                u.pb(matIdx[i][0]);
                v.pb(matIdx[i+1][0]);
                a.pb(1);
                b.pb(2*i+3);
                unite(matIdx[i][0], matIdx[i+1][0]);
                isValid = true;

                if (a.size()) {
                    bench[a[a.size()-1]][b[b.size()-1]] = true;
                }
            }
            if (mat[i][2] && mat[i+1][2]) {
                u.pb(matIdx[i][2]);
                v.pb(matIdx[i+1][2]);
                a.pb(7);
                b.pb(2*i+3);
                unite(matIdx[i][2], matIdx[i+1][2]);
                isValid = true;

                if (a.size()) {
                    bench[a[a.size()-1]][b[b.size()-1]] = true;
                }
            }

            if (!isValid && mat[i][1] && mat[i+1][1]) {
                u.pb(matIdx[i][1]);
                v.pb(matIdx[i+1][1]);
                if (!bench[3][2*i+3])
                    a.pb(3);
                else if (!bench[5][2*i+3])
                    a.pb(5);
                else
                    res = false;
                b.pb(2*i+3);
                unite(matIdx[i][1], matIdx[i+1][1]);
                if (a.size()) {
                    bench[a[a.size()-1]][b[b.size()-1]] = true;
                }
            }
        }



        for (int i = 0; i < n-1; i++) {
            res &= find(i) == find(i+1);
        }
    }

    if (!res) return 0;

    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