Submission #855461

#	Time	Username	Problem	Language	Result	Execution time	Memory
855461		Alfraganus	Bomb (IZhO17_bomb)	C++17	33 / 100	133 ms	104952 KiB

bomb

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

#define endl '\n'
#define int long long
#define fs first
#define ss second
#define all(a) a.begin(), a.end()
#define print(a)          \
    for (auto x : a)      \
        cout << x << ' '; \
    cout << endl;

#define printmp(a)   \
    for (auto x : a) \
        cout << x.fs << ' ' << x.ss << endl;

void solve(){
    int n, m;
    cin >> n >> m;
    vector<vector<char>> a(n, vector<char> (m));
    for(int i = 0; i < n; i ++)
        for(int j = 0; j < m; j ++)
            cin >> a[i][j];
    if(n <= 20 and m <= 20){
        int ans = 0;
        for(int i = 1; i <= n; i ++){
            for(int j = 1; j <= m; j ++){
                vector<vector<char>> b = a;
                for(int i1 = 0; i1 <= n - i; i1 ++){
                    for(int i2 = 0; i2 <= m - j; i2 ++){
                        if(b[i1][i2] != '0'){
                            bool flag = 1;
                            for(int x = 0; x < i; x ++){
                                for(int y = 0; y < j; y ++){
                                    if(b[i1 + x][i2 + y] == '0')
                                        flag = false;
                                }
                            }
                            if(flag){
                                for(int x = 0; x < i; x ++){
                                    for(int y = 0; y < j; y ++){
                                        b[i1 + x][i2 + y] = '2';
                                    }
                                }
                            }
                        }
                    }
                }
                int cnt = 0;
                for(int i = 0; i < n; i ++){
                    for(int j = 0; j < m; j ++){
                        cnt += b[i][j] == '1';
                    }
                }
                if(cnt == 0)
                    ans = max(ans, i * j);
            }
        }
        cout << ans;
        return;
    }
    vector<vector<int>> dp_right(n, vector<int>(m)), dp_down(n, vector<int>(m));
    for(int i = n - 1; i >= 0; i --){
        for(int j = m - 1; j >= 0; j --){
            if(a[i][j] == '1'){
                dp_right[i][j] = (j == m - 1 ? 0 : dp_right[i][j + 1]) + 1;
                dp_down[i][j] = (i == n - 1 ? 0 : dp_down[i + 1][j]) + 1;
            }
            else{
                dp_right[i][j] = 0;
                dp_down[i][j] = 0;
            }
        }
    }

    int x = m, y = n;
    for(int i = 0; i < n; i ++){
        for(int j = 0; j < m; j ++){
            if(a[i][j] == '1'){
                if(j == 0 or a[i][j - 1] == '0')
                    x = min(x, dp_right[i][j]);
                if(i == 0 or a[i - 1][j] == '0')
                    y = min(y, dp_down[i][j]);
            }
        }
    }
    cout << x * y << endl;
}

signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    // freopen("bomb.in", "r", stdin);
    // freopen("bomb.out", "w", stdout);
    int t = 1;
    // cin >> t;
    while(t --){
        solve();
        cout << endl;
    }
}

• Subtask 1: 33 / 100