Submission #526613

#	Time	Username	Problem	Language	Result	Execution time	Memory
526613		dostigator	Bomb (IZhO17_bomb)	C++17	33 / 100	1108 ms	110536 KiB

bomb

    #include <bits/stdc++.h>                            
     
    #define pb push_back
    #define sz(v) (int)v.size()
    #define all(v) v.begin(),v.end()
    #define rall(v) v.rbegin(),v.rend()
    #define x first
    #define y second
    #define int long long
    #define nl "\n"
     
    using namespace std;
     
    typedef long long ll;
    typedef pair<long long, long long> pll;
    typedef pair <ll, ll> pii;
     
    const int N = (int)1e6 + 7;
    const int M = (int)5e6 + 7;
    const ll MOD = (ll)1e9 + 7;                    
    const int inf = (int)1e9 + 7;
    const ll INF = (ll)3e18 + 7;
     
    pii dir[] = {{-1, -1}, {1, 1}, {-1, 1}, {1, -1}};
     
    int n, m;
    char c[2501][2501];
    int used[2501][2501], w[2501][2501];
     
    int get(int x1, int y1, int x2, int y2) {
    	return w[x2][y2] - w[x2][y1-1] - w[x1-1][y2] + w[x1-1][y1-1];
    }
     
    void upd(int x1, int y1, int x2, int y2) {
    	used[x1][y1]++;
    	used[x1][y2+1]--;
    	used[x2+1][y1]--;
    	used[x2+1][y2+1]++;
    }
     
    void solve() {           
    	cin >> n >> m;
    	for(int i = 1; i <= n; ++i) {
    		for(int j = 1; j <= m; ++j) {
    			cin >> c[i][j];
    			w[i][j] = w[i-1][j] + w[i][j-1] - w[i-1][j-1] + (c[i][j] == '1');
    		}
    	}
    	int ans = inf;
    	if(n == 1) {
    		int cur = 0;
    		for(int i = 1; i <= m; ++i) {
    			if(c[1][i] == '1') cur++;
    			else {
    				if(cur > 0) ans = min(ans, cur);
    				cur = 0;
    			}
    		}
    		if(c[1][m] == '1') ans = min(ans, cur);
    		cout << ans << nl;		
    		return;
    	}
    	if(m == 1) {
    		int cur = 0;
    		for(int i = 1; i <= n; ++i) {
    			if(c[i][1] == '1') cur++;
    			else {
    				if(cur > 0) ans = min(ans, cur);
    				cur = 0;
    			}
    		}                                      		
    		if(c[n][1] == '1') ans = min(ans, cur);
    		cout << ans << nl;		
    		return;
    	}
    	ans = 0;
    	int l = 1, r = n;
    	while(l <= r) {
    		int e = (l + r) >> 1;
    		int L = 1, R = m;
    		bool cur = 0;
    		while(L <= R) {
    		    int f = (L + R) >> 1;
    			for(int i = 1; i <= n; ++i) fill(used[i] + 1, used[i] + 1 + m, 0);
    			for(int i = 1; i <= n; ++i) {
    				for(int j = 1; j <= m; ++j) {
    			        if(i + e - 1 > n || j + f - 1 > m) break;
    					int x = get(i, j, i + e - 1, j + f - 1);
    					if(x == e * f) {
    						upd(i, j, i + e - 1, j + f - 1);					
    					}					
    				}
    			}
    	        for(int i = 1; i <= n; ++i) {
    	        	for(int j = 1; j <= m; ++j) {
    	        		used[i][j] += used[i-1][j] + used[i][j-1] - used[i-1][j-1];
    	        	}
    	        }
    	        bool ok = 1;
    			for(int i = 1; i <= n && ok; ++i) {
    				for(int j = 1; j <= m && ok; ++j) {
    					if(c[i][j] == '1') ok &= (used[i][j] > 0);
    				}
    			}
    			if(ok) {
    				cur = 1;
    				ans = max(ans, e * f);
    				L = f + 1;
    			} else
    				R = f - 1;
    		}
    		if(cur)
    			l = e + 1;
    		else
    			r = e - 1;
    	}
    	if(n <= 100 && m <= 100) {
    		for(int e = 1; e <= n; ++e) {
        		for(int f = 1; f <= n; ++f) {
        			bool ok = 1;
        			for(int i = 1; i <= n; ++i) fill(used[i] + 1, used[i] + 1 + m, 0);
        			for(int i = 1; i <= n; ++i) {
        				for(int j = 1; j <= m; ++j) {
        			        if(i + e - 1 > n || j + f - 1 > m) break;
        					int x = get(i, j, i + e - 1, j + f - 1);
        					if(x == e * f) {
        						upd(i, j, i + e - 1, j + f - 1);					
        					}					
        				}
        			}
        	        for(int i = 1; i <= n; ++i) {
        	        	for(int j = 1; j <= m; ++j) {
        	        		used[i][j] += used[i-1][j] + used[i][j-1] - used[i-1][j-1];
        	        	}
        	        }
        			for(int i = 1; i <= n && ok; ++i) {
        				for(int j = 1; j <= m && ok; ++j) {
        					if(c[i][j] == '1') ok &= (used[i][j] > 0);
        				}
        			}
        			if(ok) {
        				ans = max(ans, e * f);
        				//cout << e << ' ' << f << nl;
        			}
        		}
            }
    	}
    	cout << ans << nl;
    }                                                                              
                    
    signed main() {                   
    	ios_base::sync_with_stdio(NULL);
        cin.tie(0);
        cout.tie(0);
       	int test = 1;
    	//cin >> test;
    	for(int i = 1; i <= test; ++i) {
            //cout << "Case " << i << ": ";
            solve();
        }
        return 0;
    }

• Subtask 1: 33 / 100