Submission #907305

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
907305	2024-01-15T11:07:46 Z	daoquanglinh2007	Bomb (IZhO17_bomb)	C++17	68 / 100	610 ms	55896 KB

bomb

#include <bits/stdc++.h>
using namespace std;
 
const int NM = 2500, inf = 1e9+7;
 
int N, M, f[NM+5][NM+5], dp[NM+5][NM+5], ans = 0, H = +inf, W = +inf;
char a[NM+5][NM+5];
 
int getf(int x, int y, int u, int v){
	return f[u][v]-f[x-1][v]-f[u][y-1]+f[x-1][y-1];
}
 
bool check(int r, int c){
	for (int i = 1; i <= N; i++)
		for (int j = 1; j <= M; j++) dp[i][j] = 0;
	
	for (int i = 1; i+r-1 <= N; i++)
		for (int j = 1; j+c-1 <= M; j++)
			if (getf(i, j, i+r-1, j+c-1) == r*c){
				dp[i][j]++;
				dp[i+r][j]--;
				dp[i][j+c]--;
				dp[i+r][j+c]++;
			}
	for (int i = 1; i <= N; i++)
		for (int j = 1; j <= M; j++){
			dp[i][j] += dp[i-1][j]+dp[i][j-1]-dp[i-1][j-1];
			if (dp[i][j] == 0 && a[i][j] == '1') return 0;
		}
	return 1;
}
 
void preprocess(){
	for (int j = 1; j <= M; j++)
		for (int i = 1; i <= N; i++){
			if (a[i][j] == '0') continue;
			int k = i;
			while (k <= N && a[k][j] == '1') k++;
			H = min(H, k-i);
			i = k-1;
		}
	for (int i = 1; i <= N; i++)
		for (int j = 1; j <= M; j++){
			if (a[i][j] == '0') continue;
			int k = j;
			while (k <= M && a[i][k] == '1') k++;
			W = min(W, k-j);
			j = k-1;
		}
}
 
int main(){
//	freopen("BOMB.inp", "r", stdin);
//	freopen("BOMB.ans", "w", stdout);
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	
	cin >> N >> M;
	for (int i = 1; i <= N; i++)
		for (int j = 1; j <= M; j++){
			cin >> a[i][j];
			if (a[i][j] == '1') f[i][j] = 1;
		}
	preprocess();
	for (int i = 1; i <= N; i++)
		for (int j = 1; j <= M; j++)
			f[i][j] += f[i][j-1]+f[i-1][j]-f[i-1][j-1];
			
	if (N <= 450 && M <= 450){
		int j = W;
		for (int i = 1; i <= H; i++){
			while (j > 0 && !check(i, j)) j--;
			ans = max(ans, i*j);
		}
		cout << ans;
		return 0;
	}
			
	int l = 1, r = W;
	while (l <= r){
		int mid = (l+r)/2;
		if (check(H, mid)){
			ans = max(ans, H*mid);
			l = mid+1;
		}
		else r = mid-1;
	}
	l = 1, r = H;
	while (l <= r){
		int mid = (l+r)/2;
		if (check(mid, W)){
			ans = max(ans, mid*W);
			l = mid+1;
		}
		else r = mid-1;
	}
	cout << ans;
	return 0;
}

Subtask #1

68.0 / 100.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	1 ms	4444 KB	Output is correct
2	Correct	1 ms	4444 KB	Output is correct
3	Correct	9 ms	54620 KB	Output is correct
4	Correct	9 ms	54620 KB	Output is correct
5	Correct	1 ms	4444 KB	Output is correct
6	Correct	1 ms	4444 KB	Output is correct
7	Correct	1 ms	4444 KB	Output is correct
8	Correct	1 ms	4444 KB	Output is correct
9	Correct	1 ms	4440 KB	Output is correct
10	Correct	1 ms	4444 KB	Output is correct
11	Correct	1 ms	4444 KB	Output is correct
12	Correct	1 ms	4444 KB	Output is correct
13	Correct	2 ms	4440 KB	Output is correct
14	Correct	1 ms	4440 KB	Output is correct
15	Correct	1 ms	4696 KB	Output is correct
16	Correct	2 ms	6492 KB	Output is correct
17	Correct	2 ms	8796 KB	Output is correct
18	Correct	2 ms	8796 KB	Output is correct
19	Correct	3 ms	10844 KB	Output is correct
20	Correct	3 ms	10848 KB	Output is correct
21	Correct	2 ms	6860 KB	Output is correct
22	Correct	3 ms	10844 KB	Output is correct
23	Correct	3 ms	10840 KB	Output is correct
24	Correct	3 ms	10844 KB	Output is correct
25	Correct	5 ms	10844 KB	Output is correct
26	Correct	3 ms	10844 KB	Output is correct
27	Correct	4 ms	15008 KB	Output is correct
28	Correct	8 ms	14940 KB	Output is correct
29	Correct	52 ms	14988 KB	Output is correct
30	Correct	137 ms	14936 KB	Output is correct
31	Correct	77 ms	14936 KB	Output is correct
32	Correct	89 ms	14980 KB	Output is correct
33	Correct	167 ms	17236 KB	Output is correct
34	Correct	8 ms	13404 KB	Output is correct
35	Correct	50 ms	16988 KB	Output is correct
36	Correct	50 ms	19036 KB	Output is correct
37	Correct	1 ms	6488 KB	Output is correct
38	Correct	589 ms	55464 KB	Output is correct
39	Correct	1 ms	6488 KB	Output is correct
40	Correct	44 ms	27480 KB	Output is correct
41	Correct	1 ms	6492 KB	Output is correct
42	Correct	4 ms	10844 KB	Output is correct
43	Correct	610 ms	55700 KB	Output is correct
44	Correct	235 ms	19088 KB	Output is correct
45	Incorrect	362 ms	55436 KB	Output isn't correct
46	Correct	360 ms	55708 KB	Output is correct
47	Incorrect	374 ms	55656 KB	Output isn't correct
48	Correct	350 ms	55412 KB	Output is correct
49	Correct	273 ms	55636 KB	Output is correct
50	Correct	390 ms	55692 KB	Output is correct
51	Correct	389 ms	55452 KB	Output is correct
52	Correct	358 ms	55424 KB	Output is correct
53	Correct	363 ms	55632 KB	Output is correct
54	Correct	375 ms	55696 KB	Output is correct
55	Correct	349 ms	55660 KB	Output is correct
56	Correct	486 ms	55660 KB	Output is correct
57	Correct	413 ms	55656 KB	Output is correct
58	Correct	432 ms	55668 KB	Output is correct
59	Correct	418 ms	55700 KB	Output is correct
60	Correct	399 ms	55656 KB	Output is correct
61	Correct	362 ms	55632 KB	Output is correct
62	Correct	568 ms	55656 KB	Output is correct
63	Correct	608 ms	55704 KB	Output is correct
64	Correct	506 ms	55652 KB	Output is correct
65	Correct	331 ms	55656 KB	Output is correct
66	Correct	370 ms	55664 KB	Output is correct
67	Correct	369 ms	55892 KB	Output is correct
68	Correct	411 ms	55632 KB	Output is correct
69	Correct	418 ms	55452 KB	Output is correct
70	Incorrect	213 ms	49744 KB	Output isn't correct
71	Incorrect	351 ms	55896 KB	Output isn't correct
72	Incorrect	361 ms	55652 KB	Output isn't correct
73	Incorrect	347 ms	55456 KB	Output isn't correct
74	Incorrect	359 ms	55452 KB	Output isn't correct
75	Incorrect	391 ms	55716 KB	Output isn't correct
76	Incorrect	395 ms	55636 KB	Output isn't correct
77	Incorrect	392 ms	55636 KB	Output isn't correct
78	Incorrect	394 ms	55716 KB	Output isn't correct
79	Incorrect	250 ms	55632 KB	Output isn't correct
80	Incorrect	271 ms	55656 KB	Output isn't correct
81	Incorrect	299 ms	55432 KB	Output isn't correct
82	Incorrect	397 ms	55716 KB	Output isn't correct
83	Incorrect	423 ms	55884 KB	Output isn't correct
84	Incorrect	225 ms	55632 KB	Output isn't correct
85	Incorrect	360 ms	55660 KB	Output isn't correct
86	Incorrect	251 ms	55632 KB	Output isn't correct
87	Correct	342 ms	55696 KB	Output is correct
88	Incorrect	366 ms	55464 KB	Output isn't correct
89	Incorrect	321 ms	55888 KB	Output isn't correct
90	Incorrect	253 ms	50096 KB	Output isn't correct
91	Incorrect	373 ms	55656 KB	Output isn't correct
92	Incorrect	339 ms	55440 KB	Output isn't correct
93	Incorrect	266 ms	55656 KB	Output isn't correct
94	Incorrect	332 ms	55656 KB	Output isn't correct
95	Incorrect	402 ms	55632 KB	Output isn't correct
96	Incorrect	376 ms	55636 KB	Output isn't correct
97	Incorrect	254 ms	55652 KB	Output isn't correct
98	Incorrect	413 ms	55700 KB	Output isn't correct
99	Incorrect	328 ms	55660 KB	Output isn't correct
100	Incorrect	264 ms	55656 KB	Output isn't correct