Submission #907370

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
907370	2024-01-15T12:37:44 Z	daoquanglinh2007	Bomb (IZhO17_bomb)	C++17	72 / 100	968 ms	55900 KB

bomb

#pragma GCC optimize("Ofast")
#pragma GCC target("sse4")

#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

72.0 / 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	4440 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	4444 KB	Output is correct
12	Correct	1 ms	4444 KB	Output is correct
13	Correct	1 ms	4440 KB	Output is correct
14	Correct	1 ms	4444 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	6748 KB	Output is correct
22	Correct	2 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	4 ms	10844 KB	Output is correct
26	Correct	2 ms	10844 KB	Output is correct
27	Correct	4 ms	14940 KB	Output is correct
28	Correct	7 ms	13148 KB	Output is correct
29	Correct	38 ms	14936 KB	Output is correct
30	Correct	98 ms	14936 KB	Output is correct
31	Correct	55 ms	13656 KB	Output is correct
32	Correct	60 ms	14992 KB	Output is correct
33	Correct	114 ms	17072 KB	Output is correct
34	Correct	7 ms	13404 KB	Output is correct
35	Correct	48 ms	16220 KB	Output is correct
36	Correct	31 ms	19192 KB	Output is correct
37	Correct	2 ms	6488 KB	Output is correct
38	Correct	296 ms	55632 KB	Output is correct
39	Correct	1 ms	6492 KB	Output is correct
40	Correct	232 ms	27308 KB	Output is correct
41	Correct	1 ms	6492 KB	Output is correct
42	Correct	4 ms	10844 KB	Output is correct
43	Correct	433 ms	55636 KB	Output is correct
44	Correct	150 ms	19088 KB	Output is correct
45	Incorrect	959 ms	55716 KB	Output isn't correct
46	Correct	276 ms	55636 KB	Output is correct
47	Incorrect	951 ms	55684 KB	Output isn't correct
48	Correct	708 ms	55652 KB	Output is correct
49	Correct	203 ms	55656 KB	Output is correct
50	Correct	736 ms	55660 KB	Output is correct
51	Correct	734 ms	55656 KB	Output is correct
52	Correct	688 ms	55656 KB	Output is correct
53	Correct	695 ms	55892 KB	Output is correct
54	Correct	951 ms	55708 KB	Output is correct
55	Correct	956 ms	55660 KB	Output is correct
56	Correct	292 ms	55692 KB	Output is correct
57	Correct	941 ms	55696 KB	Output is correct
58	Correct	964 ms	55892 KB	Output is correct
59	Correct	965 ms	55720 KB	Output is correct
60	Correct	272 ms	55712 KB	Output is correct
61	Correct	271 ms	55656 KB	Output is correct
62	Correct	358 ms	55608 KB	Output is correct
63	Correct	359 ms	55424 KB	Output is correct
64	Correct	348 ms	55636 KB	Output is correct
65	Correct	650 ms	55652 KB	Output is correct
66	Correct	315 ms	55656 KB	Output is correct
67	Correct	799 ms	55724 KB	Output is correct
68	Correct	826 ms	55688 KB	Output is correct
69	Correct	783 ms	55652 KB	Output is correct
70	Incorrect	952 ms	48704 KB	Output isn't correct
71	Incorrect	954 ms	55700 KB	Output isn't correct
72	Incorrect	960 ms	55664 KB	Output isn't correct
73	Incorrect	956 ms	55432 KB	Output isn't correct
74	Incorrect	952 ms	55684 KB	Output isn't correct
75	Incorrect	957 ms	55888 KB	Output isn't correct
76	Incorrect	956 ms	55660 KB	Output isn't correct
77	Incorrect	958 ms	55660 KB	Output isn't correct
78	Incorrect	954 ms	55656 KB	Output isn't correct
79	Incorrect	958 ms	55660 KB	Output isn't correct
80	Incorrect	959 ms	55660 KB	Output isn't correct
81	Incorrect	958 ms	55888 KB	Output isn't correct
82	Incorrect	961 ms	55892 KB	Output isn't correct
83	Incorrect	954 ms	55900 KB	Output isn't correct
84	Incorrect	961 ms	55700 KB	Output isn't correct
85	Incorrect	951 ms	55656 KB	Output isn't correct
86	Correct	960 ms	55892 KB	Output is correct
87	Correct	960 ms	55656 KB	Output is correct
88	Incorrect	957 ms	55656 KB	Output isn't correct
89	Incorrect	958 ms	55656 KB	Output isn't correct
90	Incorrect	950 ms	49872 KB	Output isn't correct
91	Incorrect	960 ms	55656 KB	Output isn't correct
92	Incorrect	959 ms	55656 KB	Output isn't correct
93	Correct	962 ms	55656 KB	Output is correct
94	Incorrect	951 ms	55892 KB	Output isn't correct
95	Incorrect	958 ms	55692 KB	Output isn't correct
96	Incorrect	954 ms	55660 KB	Output isn't correct
97	Correct	951 ms	55656 KB	Output is correct
98	Incorrect	968 ms	55836 KB	Output isn't correct
99	Incorrect	957 ms	55660 KB	Output isn't correct
100	Correct	953 ms	55696 KB	Output is correct