Submission #1065833

#	Time	Username	Problem	Language	Result	Execution time	Memory
1065833		deera	Soccer Stadium (IOI23_soccer)	C++17	6 / 100	205 ms	31828 KiB

soccer

#include <bits/stdc++.h>
using namespace std;

struct Pos {
    int x, y;
    Pos(int x, int y) : x(x), y(y) {}
};

bool BORDER[2001][2001] = {0};
int   COLOR[2001][2001] = {0};

void paint(int x, int y, int color) {
    if (x < 0 || x >= 2001 || y < 0 || y >= 2001) return;
    if (COLOR[x][y] || !BORDER[x][y]) return;

    COLOR[x][y] = color;
    paint(x - 1, y, color);
    paint(x + 1, y, color);
    paint(x, y - 1, color);
    paint(x, y + 1, color);
}

int biggest_stadium(int N, vector<vector<int>> F) {
    vector<Pos> trees;
    for (int i = 0; i < N; i++) for (int j = 0; j < N; j++) {
        if (F[i][j] == 1) trees.push_back({i, j});
    }

    for (auto tree : trees) {
        cerr << tree.x << " " << tree.y << endl;
    }

    if (trees.size() == 0) return N * N;
    if (trees.size() == 1) {
        int x = trees[0].x, y = trees[0].y;

        int n = N - 1;
        int a = (abs(x - 0) + 1) * (abs(y - 0) + 1);
        int b = (abs(x - 0) + 1) * (abs(y - n) + 1);
        int c = (abs(x - n) + 1) * (abs(y - 0) + 1);
        int d = (abs(x - n) + 1) * (abs(y - n) + 1);


        return N * N - min({a, b, c, d});
    }

    // for 25% of marks
    // bool BORDER[2001][2001] = {0};
    queue<Pos> q;
    set<pair<int, int>> once;

    for (int i = 0; i < N; i++) for (int j = 0; j < N; j++) {
        if (F[i][j] == 1 && (i == 0 || i == N - 1 || j == 0 || j == N - 1)) {
            once.insert({i, j});
        }
    }

    for (int i: {0, N - 1}) for (int j: {0, N - 1}) if (F[i][j]) {
        q.push({i, j});
        BORDER[i][j] = true;
    }


    while (!q.empty()) {
        Pos p = q.front(); q.pop();
        int x = p.x, y = p.y;

        for (int i: {-1, 0, 1}) for (int j: {-1, 0, 1}) {
            if (i == 0 && j == 0) continue;
            if (i != 0 && j != 0) continue;
            if (x + i < 0 || x + i >= N || y + j < 0 || y + j >= N) continue;
            
            if (F[x + i][y + j] && !BORDER[x + i][y + j]) {
                if (once.find({x + i, y + j}) != once.end()) {
                    q.push({x + i, y + j});
                    BORDER[x + i][y + j] = true;
                } else {
                    once.insert({x + i, y + j});
                }
            }
        }
    }



    int all = true;
    for (Pos t: trees)
        if (!BORDER[t.x][t.y]) {all = false; break;};
    
    if (!all) return 0;

    int color = 1;
    for (int i: {0, N - 1}) for (int j: {0, N - 1})
        if (!COLOR[i][j] && BORDER[i][j])
            paint(i, j, color++);

    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            cerr << COLOR[i][j] << " ";
        }
        cerr << endl;
    }

    int a, b;
    for (int k = 1; k < N - 1; k++) {
        for (int l: {-1, 0, 1}) {
            int i = k;
            int j = k + l;
            if (i <= 0 || i >= N - 1) continue;
            if (j <= 0 || j >= N - 1) continue;
            a = COLOR[i][0]; b = COLOR[j][N-1];
            if (F[i][0] && F[j][N-1] && a != b) {
                if (a == COLOR[0][0] && b == COLOR[N-1][N-1]) all = false;
                if (a == COLOR[0][N-1] && b == COLOR[N-1][0]) all = false;

                swap(a, b);
                if (a == COLOR[0][0] && b == COLOR[N-1][N-1]) all = false;
                if (a == COLOR[0][N-1] && b == COLOR[N-1][0]) all = false;
            }

            a = COLOR[0][i]; b = COLOR[N-1][j];
            if (F[0][i] && F[N-1][j] && a != b) {
                if (a == COLOR[0][0] && b == COLOR[N-1][N-1]) all = false;
                if (a == COLOR[0][N-1] && b == COLOR[N-1][0]) all = false;

                swap(a, b);
                if (a == COLOR[0][0] && b == COLOR[N-1][N-1]) all = false;
                if (a == COLOR[0][N-1] && b == COLOR[N-1][0]) all = false;
            }
        }
    }

    if (all) return N * N - trees.size();
    else return 0;
}

• Subtask 0: 0 / 0
• Subtask 1: 6 / 6
• Subtask 2: 0 / 8
• Subtask 3: 0 / 22
• Subtask 4: 0 / 18
• Subtask 5: 0 / 16
• Subtask 6: 0 / 30