Submission #38400

#	Time	Username	Problem	Language	Result	Execution time	Memory
38400		Talant	Bomb (IZhO17_bomb)	C++14	32 / 100	1000 ms	131072 KiB

bomb

#include <bits/stdc++.h>

#define fr first
#define sc second
#define OK puts("OK");
#define pb push_back
#define mk make_pair

using namespace std;

typedef long long ll;

const int inf = (int)1e9 + 7;
const int N = (int)1e6 + 10;

int n,m;
char a[2501][2501];
int t[2501][2501];
int c[2501][2501];
int mx,mn = inf,mn1 = inf;
vector <pair<int,int> > v;

bool check (int h,int w) {
        for (int i = h; i <= n; i ++) {
                for (int j = w; j <= m; j ++) {
                        if (c[i][j] - c[i - h][j] - c[i][j - w] + c[i - h][j - w] == (h * w)) {
                                for (int l = i - h + 1; l <= i; l ++) {
                                        for (int r = j - w + 1; r <= j; r ++) {
                                                t[l][r] = -1;
                                        }
                                }
                        }
                }
        }
        int f = 0;

        for (int i = 0; i < v.size(); i ++) {
                if (t[v[i].fr][v[i].sc] == 1)
                        f = 1;
                t[v[i].fr][v[i].sc] = 1;
        }

        if (f)
                return false;
        return true;
}
int main () {
        cin >> n >> m;

        for (int i = 1; i <= n; i ++)
                scanf ("%s", a[i] + 1);

        for (int i = 1; i <= n; i ++) {
                int cnt = 0;
                for (int j = 1; j <= m; j ++) {
                        t[i][j] = int(a[i][j] - '0');
                        c[i][j] = t[i][j];
                        if (t[i][j] == 1)
                                v.pb(mk(i,j));
                        if (c[i][j] == 1)
                                cnt ++;
                        else {
                                if (cnt > 0)
                                mn = min(mn,cnt);
                        cnt = 0;
                        }
                }
                if (cnt > 0)
                        mn = min(mn,cnt);
        }
        for (int i = 1; i <= m; i ++) {
                int cnt = 0;
                for (int j = 1; j <= n; j ++) {
                        if (c[j][i] == 1)
                                cnt ++;
                        else {
                                if (cnt > 0)
                                mn1 = min(mn1,cnt);
                        cnt = 0;
                        }
                }
                if (cnt > 0)
                        mn1 = min(mn1,cnt);
        }
        if (mn == inf)
                mn = 0;
        if (mn1 == inf)
                mn1 = 0;

        for (int i = 1; i <= n; i ++)
                for (int j = 2; j <= m; j ++)
                        c[i][j] += c[i][j - 1];

        for (int i = 2; i <= n; i ++)
                for (int j = 1; j <= m; j ++)
                        c[i][j] += c[i - 1][j];

        for (int i = 1; i <= mn1; i ++) {
                for (int j = 1; j <= mn; j ++) {
                         if (mx >= i * j)
                                continue;
                         if (check(i,j))
                                mx = max(mx,i * j);
                }
        }
        cout << mx << endl;
}

Compilation message (stderr)

bomb.cpp: In function 'bool check(int, int)':
bomb.cpp:37:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < v.size(); i ++) {
                           ^
bomb.cpp: In function 'int main()':
bomb.cpp:51:39: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
                 scanf ("%s", a[i] + 1);
                                       ^

• Subtask 1: 32 / 100