Submission #1037240

#	Time	Username	Problem	Language	Result	Execution time	Memory
1037240		Alfraganus	Bomb (IZhO17_bomb)	C++17	49 / 100	1067 ms	104704 KiB

bomb

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

#define int long long
#define str string
#define fastio ios::sync_with_stdio(0), cin.tie(0);
#define fs first
#define ss second
#define endl '\n'
#define all(x) (x).begin(), (x).end()
#define len(x) x.size()

#define print(a)          \
    for (auto &x : a)     \
        cout << x << " "; \
    cout << endl;

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

const int mod = 1e9 + 7;

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 <= 450 and m <= 450){
        vector<vector<int>> pref(n + 1, vector<int> (m + 1));
        for(int i = 0; i < n; i ++)
            for(int j = 0; j < m; j ++)
                pref[i + 1][j + 1] = pref[i][j + 1] + pref[i + 1][j] - pref[i][j] + (a[i][j] == '0');
        vector<vector<array<int, 2>>> dp(n, vector<array<int, 2>> (m, {0, 0}));
        int ans = 1;
        for(int i = 1; i <= n; i ++){
            for(int j = 1; j <= m; j ++){
                bool flag = 1;
                for(int x = 0; x < n; x ++){
                    for(int y = 0; y < m; y ++){
                        if(x + i <= n and y + j <= m and pref[x + i][y + j] - pref[x + i][y] - pref[x][y + j] + pref[x][y] == 0)
                            dp[x][y] = {i, j};
                        else{
                            dp[x][y] = {0, 0};
                            if(y > 0 and dp[x][y - 1][1] > 1)
                                dp[x][y] = {dp[x][y - 1][0], dp[x][y - 1][1] - 1};
                            if(x > 0 and dp[x - 1][y][0] > 1)
                                dp[x][y] = max(dp[x][y], {dp[x - 1][y][0] - 1, dp[x - 1][y][1]});
                        }
                        if(a[x][y] == '1' and dp[x][y][0] == 0 and dp[x][y][1] == 0){
                            flag = 0;
                            break;
                        }
                    }
                    if(!flag)
                        break;
                }
                if(flag)
                    ans = max(ans, i * j);
                else
                    break;
            }
        }
        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()
{
    fastio;
    #ifdef Javohir
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #endif
    int t = 1;
    // cin >> t;
    while (t--)
    {
        solve();
        cout << endl;
    }
}

• Subtask 1: 49 / 100