Submission #907306

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
907306	2024-01-15T11:09:33 Z	daoquanglinh2007	Bomb (IZhO17_bomb)	C++17	68 / 100	629 ms	55968 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{
			if (H-1 > 0 && check(H-1, mid)) ans = max(ans, (H-1)*mid);
			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	4440 KB	Output is correct
2	Correct	1 ms	4444 KB	Output is correct
3	Correct	9 ms	54440 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	4444 KB	Output is correct
10	Correct	2 ms	4440 KB	Output is correct
11	Correct	1 ms	4440 KB	Output is correct
12	Correct	1 ms	4444 KB	Output is correct
13	Correct	1 ms	4444 KB	Output is correct
14	Correct	1 ms	4444 KB	Output is correct
15	Correct	1 ms	4444 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	10840 KB	Output is correct
20	Correct	3 ms	10840 KB	Output is correct
21	Correct	2 ms	6748 KB	Output is correct
22	Correct	2 ms	10844 KB	Output is correct
23	Correct	4 ms	10844 KB	Output is correct
24	Correct	3 ms	10840 KB	Output is correct
25	Correct	5 ms	10840 KB	Output is correct
26	Correct	3 ms	10844 KB	Output is correct
27	Correct	4 ms	14940 KB	Output is correct
28	Correct	8 ms	14768 KB	Output is correct
29	Correct	57 ms	15184 KB	Output is correct
30	Correct	133 ms	14936 KB	Output is correct
31	Correct	83 ms	14940 KB	Output is correct
32	Correct	90 ms	14936 KB	Output is correct
33	Correct	176 ms	17236 KB	Output is correct
34	Correct	7 ms	13400 KB	Output is correct
35	Correct	55 ms	17068 KB	Output is correct
36	Correct	51 ms	19036 KB	Output is correct
37	Correct	1 ms	6492 KB	Output is correct
38	Correct	570 ms	55656 KB	Output is correct
39	Correct	1 ms	6492 KB	Output is correct
40	Correct	49 ms	27228 KB	Output is correct
41	Correct	2 ms	6488 KB	Output is correct
42	Correct	5 ms	10844 KB	Output is correct
43	Correct	629 ms	55656 KB	Output is correct
44	Correct	240 ms	19032 KB	Output is correct
45	Incorrect	464 ms	55656 KB	Output isn't correct
46	Correct	369 ms	55652 KB	Output is correct
47	Incorrect	425 ms	55636 KB	Output isn't correct
48	Correct	405 ms	55700 KB	Output is correct
49	Correct	260 ms	55456 KB	Output is correct
50	Correct	429 ms	55656 KB	Output is correct
51	Correct	433 ms	55632 KB	Output is correct
52	Correct	421 ms	55692 KB	Output is correct
53	Correct	400 ms	55636 KB	Output is correct
54	Correct	470 ms	55720 KB	Output is correct
55	Correct	429 ms	55444 KB	Output is correct
56	Correct	476 ms	55632 KB	Output is correct
57	Correct	467 ms	55652 KB	Output is correct
58	Correct	501 ms	55652 KB	Output is correct
59	Correct	483 ms	55912 KB	Output is correct
60	Correct	393 ms	55428 KB	Output is correct
61	Correct	379 ms	55656 KB	Output is correct
62	Correct	570 ms	55660 KB	Output is correct
63	Correct	624 ms	55656 KB	Output is correct
64	Correct	516 ms	55656 KB	Output is correct
65	Correct	375 ms	55892 KB	Output is correct
66	Correct	411 ms	55464 KB	Output is correct
67	Correct	445 ms	55892 KB	Output is correct
68	Correct	477 ms	55652 KB	Output is correct
69	Correct	476 ms	55424 KB	Output is correct
70	Incorrect	260 ms	49752 KB	Output isn't correct
71	Incorrect	443 ms	55660 KB	Output isn't correct
72	Incorrect	449 ms	55892 KB	Output isn't correct
73	Incorrect	406 ms	55636 KB	Output isn't correct
74	Incorrect	467 ms	55636 KB	Output isn't correct
75	Incorrect	469 ms	55448 KB	Output isn't correct
76	Incorrect	487 ms	55656 KB	Output isn't correct
77	Incorrect	513 ms	55652 KB	Output isn't correct
78	Incorrect	512 ms	55468 KB	Output isn't correct
79	Incorrect	304 ms	55664 KB	Output isn't correct
80	Incorrect	279 ms	55632 KB	Output isn't correct
81	Incorrect	367 ms	55656 KB	Output isn't correct
82	Incorrect	502 ms	55636 KB	Output isn't correct
83	Incorrect	508 ms	55724 KB	Output isn't correct
84	Incorrect	300 ms	55440 KB	Output isn't correct
85	Incorrect	437 ms	55652 KB	Output isn't correct
86	Incorrect	317 ms	55632 KB	Output isn't correct
87	Correct	452 ms	55652 KB	Output is correct
88	Incorrect	468 ms	55652 KB	Output isn't correct
89	Incorrect	398 ms	55660 KB	Output isn't correct
90	Incorrect	328 ms	49868 KB	Output isn't correct
91	Incorrect	447 ms	55652 KB	Output isn't correct
92	Incorrect	429 ms	55892 KB	Output isn't correct
93	Incorrect	321 ms	55448 KB	Output isn't correct
94	Incorrect	413 ms	55892 KB	Output isn't correct
95	Incorrect	509 ms	55660 KB	Output isn't correct
96	Incorrect	465 ms	55968 KB	Output isn't correct
97	Incorrect	313 ms	55636 KB	Output isn't correct
98	Incorrect	523 ms	55696 KB	Output isn't correct
99	Incorrect	412 ms	55636 KB	Output isn't correct
100	Incorrect	318 ms	55428 KB	Output isn't correct