Submission #907314

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
907314	2024-01-15T11:17:52 Z	daoquanglinh2007	Bomb (IZhO17_bomb)	C++17	70 / 100	978 ms	55892 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;
	}
	int j = W-1;
	for (int i = 1; i < H; i++){
		if (i*j <= ans) continue;
		while (j > 0 && !check(i, j)){
			if ((double)clock()/CLOCKS_PER_SEC > 0.95) break;
			j--;
		}
		if ((double)clock()/CLOCKS_PER_SEC > 0.95) break;
		ans = max(ans, i*j);
	}
	cout << ans;
	return 0;
}

Subtask #1

70.0 / 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	10 ms	54616 KB	Output is correct
4	Correct	9 ms	54620 KB	Output is correct
5	Correct	1 ms	4444 KB	Output is correct
6	Correct	2 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	1 ms	4444 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	4440 KB	Output is correct
15	Correct	1 ms	4444 KB	Output is correct
16	Correct	1 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	10844 KB	Output is correct
21	Correct	2 ms	6744 KB	Output is correct
22	Correct	3 ms	10840 KB	Output is correct
23	Correct	3 ms	10844 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	14936 KB	Output is correct
28	Correct	8 ms	14996 KB	Output is correct
29	Correct	53 ms	14940 KB	Output is correct
30	Correct	128 ms	14988 KB	Output is correct
31	Correct	80 ms	14984 KB	Output is correct
32	Correct	89 ms	14940 KB	Output is correct
33	Correct	168 ms	16984 KB	Output is correct
34	Correct	7 ms	13404 KB	Output is correct
35	Correct	51 ms	16988 KB	Output is correct
36	Correct	51 ms	19036 KB	Output is correct
37	Correct	2 ms	6488 KB	Output is correct
38	Correct	577 ms	55456 KB	Output is correct
39	Correct	2 ms	6492 KB	Output is correct
40	Correct	345 ms	27528 KB	Output is correct
41	Correct	1 ms	6488 KB	Output is correct
42	Correct	5 ms	10844 KB	Output is correct
43	Correct	624 ms	55712 KB	Output is correct
44	Correct	239 ms	19036 KB	Output is correct
45	Incorrect	972 ms	55652 KB	Output isn't correct
46	Correct	383 ms	55660 KB	Output is correct
47	Incorrect	955 ms	55692 KB	Output isn't correct
48	Correct	854 ms	55868 KB	Output is correct
49	Correct	262 ms	55660 KB	Output is correct
50	Correct	893 ms	55656 KB	Output is correct
51	Correct	880 ms	55888 KB	Output is correct
52	Correct	838 ms	55892 KB	Output is correct
53	Correct	841 ms	55656 KB	Output is correct
54	Correct	968 ms	55888 KB	Output is correct
55	Correct	968 ms	55888 KB	Output is correct
56	Correct	489 ms	55888 KB	Output is correct
57	Correct	952 ms	55656 KB	Output is correct
58	Correct	963 ms	55660 KB	Output is correct
59	Correct	958 ms	55660 KB	Output is correct
60	Correct	379 ms	55636 KB	Output is correct
61	Correct	367 ms	55700 KB	Output is correct
62	Correct	556 ms	55440 KB	Output is correct
63	Correct	610 ms	55636 KB	Output is correct
64	Correct	523 ms	55652 KB	Output is correct
65	Correct	755 ms	55660 KB	Output is correct
66	Correct	412 ms	55636 KB	Output is correct
67	Correct	978 ms	55656 KB	Output is correct
68	Correct	957 ms	55888 KB	Output is correct
69	Correct	953 ms	55652 KB	Output is correct
70	Incorrect	958 ms	50004 KB	Output isn't correct
71	Incorrect	959 ms	55636 KB	Output isn't correct
72	Incorrect	950 ms	55656 KB	Output isn't correct
73	Incorrect	964 ms	55696 KB	Output isn't correct
74	Incorrect	965 ms	55708 KB	Output isn't correct
75	Incorrect	967 ms	55652 KB	Output isn't correct
76	Incorrect	965 ms	55700 KB	Output isn't correct
77	Incorrect	951 ms	55656 KB	Output isn't correct
78	Incorrect	963 ms	55888 KB	Output isn't correct
79	Incorrect	965 ms	55888 KB	Output isn't correct
80	Incorrect	954 ms	55428 KB	Output isn't correct
81	Incorrect	951 ms	55656 KB	Output isn't correct
82	Incorrect	960 ms	55656 KB	Output isn't correct
83	Incorrect	953 ms	55888 KB	Output isn't correct
84	Incorrect	956 ms	55656 KB	Output isn't correct
85	Incorrect	956 ms	55652 KB	Output isn't correct
86	Correct	951 ms	55448 KB	Output is correct
87	Correct	963 ms	55660 KB	Output is correct
88	Incorrect	966 ms	55720 KB	Output isn't correct
89	Incorrect	955 ms	55656 KB	Output isn't correct
90	Incorrect	953 ms	50004 KB	Output isn't correct
91	Incorrect	960 ms	55636 KB	Output isn't correct
92	Incorrect	974 ms	55660 KB	Output isn't correct
93	Incorrect	975 ms	55436 KB	Output isn't correct
94	Incorrect	963 ms	55892 KB	Output isn't correct
95	Incorrect	958 ms	55652 KB	Output isn't correct
96	Incorrect	963 ms	55888 KB	Output isn't correct
97	Incorrect	958 ms	55652 KB	Output isn't correct
98	Incorrect	960 ms	55656 KB	Output isn't correct
99	Incorrect	951 ms	55712 KB	Output isn't correct
100	Correct	952 ms	55888 KB	Output is correct