Submission #854575

#	Time	Username	Problem	Language	Result	Execution time	Memory
854575		The_Samurai	Bomb (IZhO17_bomb)	C++17	35 / 100	1095 ms	38608 KiB

bomb

#include "bits/stdc++.h"
using namespace std;
using ll = long long;
const int inf = 1e9, N = 1e6 + 5;

int main() {
    cin.tie(0)->sync_with_stdio(false);
#ifdef sunnatov
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#else
//    freopen("game.in", "r", stdin);
//    freopen("game.out", "w", stdout);
#endif

    int n, m;
    cin >> n >> m;
    vector<vector<char>> a(n + 1, vector<char>(m + 1));
    vector<vector<int>> pref(n + 1, vector<int>(m + 1));
    for (int i = 1; i <= n; i++) for (int j = 1; j <= m; j++) {
        cin >> a[i][j];
        pref[i][j] = pref[i][j - 1] + pref[i - 1][j] - pref[i - 1][j - 1] + (int) (a[i][j] == '1');
    }
    auto get_sum = [&](int x1, int y1, int x2, int y2) {
        return pref[x2][y2] - pref[x2][y1 - 1] - pref[x1 - 1][y2] + pref[x1 - 1][y1 - 1];
    };
    auto check = [&](int h, int w) {
        vector<vector<bool>> vis(n + 1, vector<bool>(m + 1));
        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= m; j++) {
                if (a[i][j] == '0') continue;
                if (i + h - 1 <= n and j + w - 1 <= m and get_sum(i, j, i + h - 1, j + w - 1) == h * w) {
                    for (int x = i; x < i + h; x++) {
                        for (int y = j; y < j + w; y++) {
                            vis[x][y] = true;
                        }
                    }
                }
                if (!vis[i][j]) return false;
            }
        }
        return true;
    };

    auto get = [&](int h) {
        int lx = 1, rx = m, best = 0;
        while (lx <= rx) {
            int mid = (lx + rx) >> 1;
            if (check(h, mid)) {
                best = mid;
                lx = mid + 1;
            } else {
                rx = mid - 1;
            }
        }
        return best;
    };
    int ans = 0, last = 0;
    for (int h = 1; h <= n; h++) {
        ans = max(ans, get(h) * h);
    }
    cout << ans;
}

Compilation message (stderr)

bomb.cpp: In function 'int main()':
bomb.cpp:58:18: warning: unused variable 'last' [-Wunused-variable]
   58 |     int ans = 0, last = 0;
      |                  ^~~~

• Subtask 1: 35 / 100