Submission #677771

#	Time	Username	Problem	Language	Result	Execution time	Memory
677771		bashkort	Furniture (JOI20_furniture)	C++17	100 / 100	430 ms	23760 KiB

furniture

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

constexpr int N = 1004, dx[]{0, 0, -1, 1}, dy[]{-1, 1, 0, 0};

int c[N][N], dead[N][N];

int fn[N + 7][N + 7];

void add(int i, int j) {
    for (int x = i + 1; x < N; x += x & -x) {
        for (int y = j + 1; y < N; y += y & -y) {
            fn[x][y] += 1;
        }
    }
}

int sum(int i, int j) {
    int ans = 0;
    for (int x = i + 1; x > 0; x -= x & -x) {
        for (int y = j + 1; y > 0; y -= y & -y) {
            ans += fn[x][y];
        }
    }
    return ans;
}

int rangeSum(int i1, int j1, int i2, int j2) {
    return sum(i2, j2) + sum(i1 - 1, j1 - 1) - sum(i2, j1 - 1) - sum(i1 - 1, j2);
}

bool full(int i1, int j1, int i2, int j2) {
    if (i1 > i2 || j1 > j2) return true;
    return (i2 - i1 + 1) * (j2 - j1 + 1) == rangeSum(i1, j1, i2, j2);
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, m;
    cin >> n >> m;

    queue<pair<int, int>> consider;

    for (int i = 1; i <= n; ++i) {
        for (int j = 1; j <= m; ++j) {
            cin >> c[i][j];

            if (c[i][j]) {
                consider.emplace(i, j);
            }
        }
    }
    for (int j = 2; j <= m + 1; ++j) {
        c[0][j] = 1;
        consider.emplace(0, j);
    }
    for (int i = 2; i <= n + 1; ++i) {
        c[i][0] = 1;
        consider.emplace(i, 0);
    }
    for (int j = 0; j <= m - 1; ++j) {
        c[n + 1][j] = 1;
        consider.emplace(n + 1, j);
    }
    for (int i = 0; i <= n - 1; ++i) {
        c[i][m + 1] = 1;
        consider.emplace(i, m + 1);
    }


    auto normalize = [&]() {
        while (!consider.empty()) {
            auto [i, j] = consider.front();
            consider.pop();

            if (dead[i][j]) {
                continue;
            }

            dead[i][j] = c[i][j];
            if (i && j && dead[i - 1][j] && dead[i][j - 1]) {
                dead[i][j] = 1;
            }
            if (dead[i][j + 1] && dead[i + 1][j]) {
                dead[i][j] = 1;
            }

            if (dead[i][j]) {
                for (int k = 0; k < size(dx); ++k) {
                    int ni = i + dx[k], nj = j + dy[k];
                    if (ni > 0 && nj > 0 && ni < n + 1 && nj < m + 1 && !dead[ni][nj]) {
                        consider.emplace(ni, nj);
                    }
                }
                add(i, j);
            }
        }
    };

    normalize();

    auto print = [&]() {
        for (int i = 0; i <= n + 1; ++i) {
            for (int j = 0; j <= m + 1; ++j) {
                cout << dead[i][j];
            }
            cout << endl;
        }
        cout << endl;
    };

//    print();

    int q;
    cin >> q;

    while (q--) {
        int i, j;
        cin >> i >> j;

        if (dead[i][j]) {
            c[i][j] = 1;
            cout << "1\n";
            continue;
        }

        int i1 = i + 1;
        int j1 = 1;
        int i2 = n;
        int j2 = j - 1;

        bool dont_need = false;
        if (!full(i1, j1, i2, j2)) {
            dont_need = true;
        }

        i1 = 1;
        j1 = j + 1;
        i2 = i - 1;
        j2 = m;
        if (!full(i1, j1, i2, j2)) {
            dont_need = true;
        }

        if (dont_need) {
            c[i][j] = 1;
            consider.emplace(i, j);

            normalize();

//            cout << "added: " << i << " " << j << endl;
//            print();

            cout << "1\n";
        } else {
            cout << "0\n";
        }

    }

    return 0;
}

Compilation message (stderr)

furniture.cpp: In lambda function:
furniture.cpp:93:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::size_t' {aka 'long unsigned int'} [-Wsign-compare]
   93 |                 for (int k = 0; k < size(dx); ++k) {
      |                                 ~~^~~~~~~~~~
furniture.cpp: In function 'int main()':
furniture.cpp:106:10: warning: variable 'print' set but not used [-Wunused-but-set-variable]
  106 |     auto print = [&]() {
      |          ^~~~~

• Subtask 1: 5 / 5
• Subtask 2: 95 / 95