Submission #170982

#	Time	Username	Problem	Language	Result	Execution time	Memory
170982		davitmarg	Bomb (IZhO17_bomb)	C++17	100 / 100	843 ms	74116 KiB

bomb

/*DavitMarg*/
#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <string>
#include <cstring>
#include <map>
#include <unordered_map>
#include <set>
#include <queue>
#include <iomanip>
#include <bitset>
#include <stack>
#include <cassert>
#include <iterator>
#include <fstream>
#define mod 1000000007ll
#define LL long long
#define LD long double
#define MP make_pair
#define PB push_back
#define all(v) v.begin(), v.end()
using namespace std;

const int N = 2505;

int n, m, a[N][N], nxt[N][N], lst[N][N], d[N], Y, X, ans;

int main()
{
    cin >> n >> m;

    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
        {
            char x;
            scanf(" %c", &x);
            a[i][j] += (x - '0');
        }
    X = m;
    Y = n;
    for (int i = 1; i <= n; i++)
    {
        for (int j = m; j >= 1; j--)
        {
            if (a[i][j])
            {
                nxt[i][j] = nxt[i][j + 1] + 1;
                if (a[i][j - 1] == 0)
                    X = min(nxt[i][j], X);
            }
            else
                nxt[i][j] = 0;
        }

        for (int j = 1; j <= m; j++)
            if (a[i][j])
                lst[i][j] = lst[i][j - 1] + 1;
            else
                lst[i][j] = 0;
    }

    for (int i = 1; i <= Y; i++)
        d[i] = X;

    for (int j = 1; j <= m; j++)
    {
        int y = 0, l = X, r = X;
        for (int i = 1; i <= n; i++)
        {
            if (a[i][j] == 0)
            {
                y = 0;
                l = r = X;
            }
            else
            {
                y++;
                r = min(r, nxt[i][j]);
                l = min(l, lst[i][j]);
                d[y] = min(l + r - 1, d[y]);
            }
            //cout << i << " : " << j << " = " << y << " : " << x << endl;
        }

        y = 0;
        l = X;
        r = X;
        for (int i = n; i >= 1; i--)
        {

            if (a[i][j] == 0)
            {
                y = 0;
                l = r = X;
            }
            else
            {
                y++;
                if (a[i - 1][j] == 0)
                    Y = min(y, Y);
                r = min(r, nxt[i][j]);
                l = min(l, lst[i][j]);
                d[y] = min(l + r - 1, d[y]);
            }
            //cout << i << " : " << j << " = " << y << " : " << x << endl;
        }
    }

    for (int i = 1; i <= Y; i++)
    {
        //d[i + 1] = min(d[i + 1], d[i]);
        //cout << i << " : " << d[i] << endl;
        ans = max(ans, i * d[i]);
    }

    cout << ans << endl;
    return 0;
}

/*

4 3
110
111
111
011

5 6
100000
111110
111110
111110
100000

6 5
00110
01110
11110
11011
11111
11111


9 9
000000000
000111000
000111000
011111110
011101110
011111110
000111000
000111000
000000000
 
9 9
000000000
000111000
000111000
011111110
011101110
011111110
000111000
000111000
000000000

6 6
000111
000111
001111
111100
111000
111000

6 6
000000
111000
111100
001111
000111
000111

6 6
000111
011111
011111
111000
111000
111000
 
*/

Compilation message (stderr)

bomb.cpp: In function 'int main()':
bomb.cpp:38:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf(" %c", &x);
             ~~~~~^~~~~~~~~~~

• Subtask 1: 100 / 100