Submission #907374

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
907374	2024-01-15T12:42:17 Z	daoquanglinh2007	Bomb (IZhO17_bomb)	C++17	70 / 100	971 ms	55960 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+r-1][j+c-1]++;
				dp[i+r-1][j-1]--;
				dp[i-1][j+c-1]--;
				dp[i-1][j-1]++;
			}
	for (int i = N; i >= 1; i--)
		for (int j = M; j >= 1; 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-1][j]+f[i][j-1]-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	11 ms	54620 KB	Output is correct
4	Correct	9 ms	54648 KB	Output is correct
5	Correct	1 ms	4440 KB	Output is correct
6	Correct	1 ms	4444 KB	Output is correct
7	Correct	1 ms	4444 KB	Output is correct
8	Correct	2 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	2 ms	4444 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	4440 KB	Output is correct
16	Correct	1 ms	4444 KB	Output is correct
17	Correct	2 ms	8728 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	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	3 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	6 ms	13148 KB	Output is correct
29	Correct	42 ms	15192 KB	Output is correct
30	Correct	92 ms	14980 KB	Output is correct
31	Correct	54 ms	13400 KB	Output is correct
32	Correct	54 ms	14980 KB	Output is correct
33	Correct	124 ms	17068 KB	Output is correct
34	Correct	9 ms	13404 KB	Output is correct
35	Correct	180 ms	16008 KB	Output is correct
36	Correct	31 ms	19036 KB	Output is correct
37	Correct	2 ms	4444 KB	Output is correct
38	Correct	474 ms	55656 KB	Output is correct
39	Correct	1 ms	4444 KB	Output is correct
40	Correct	238 ms	27296 KB	Output is correct
41	Correct	1 ms	4440 KB	Output is correct
42	Correct	8 ms	10840 KB	Output is correct
43	Correct	420 ms	55656 KB	Output is correct
44	Correct	155 ms	19084 KB	Output is correct
45	Incorrect	958 ms	55656 KB	Output isn't correct
46	Correct	250 ms	55660 KB	Output is correct
47	Incorrect	958 ms	55656 KB	Output isn't correct
48	Correct	711 ms	55888 KB	Output is correct
49	Correct	189 ms	55712 KB	Output is correct
50	Correct	712 ms	55472 KB	Output is correct
51	Correct	722 ms	55636 KB	Output is correct
52	Correct	689 ms	55636 KB	Output is correct
53	Correct	685 ms	55656 KB	Output is correct
54	Correct	958 ms	55656 KB	Output is correct
55	Correct	933 ms	55660 KB	Output is correct
56	Correct	323 ms	55656 KB	Output is correct
57	Correct	801 ms	55460 KB	Output is correct
58	Correct	839 ms	55660 KB	Output is correct
59	Correct	861 ms	55888 KB	Output is correct
60	Correct	263 ms	55660 KB	Output is correct
61	Correct	247 ms	55656 KB	Output is correct
62	Correct	354 ms	55960 KB	Output is correct
63	Correct	322 ms	55656 KB	Output is correct
64	Correct	325 ms	55712 KB	Output is correct
65	Correct	676 ms	55656 KB	Output is correct
66	Correct	290 ms	55672 KB	Output is correct
67	Correct	821 ms	55660 KB	Output is correct
68	Correct	808 ms	55708 KB	Output is correct
69	Correct	651 ms	55652 KB	Output is correct
70	Incorrect	951 ms	48704 KB	Output isn't correct
71	Incorrect	951 ms	55888 KB	Output isn't correct
72	Incorrect	963 ms	55660 KB	Output isn't correct
73	Incorrect	960 ms	55448 KB	Output isn't correct
74	Incorrect	953 ms	55892 KB	Output isn't correct
75	Incorrect	958 ms	55652 KB	Output isn't correct
76	Incorrect	952 ms	55888 KB	Output isn't correct
77	Incorrect	959 ms	55892 KB	Output isn't correct
78	Incorrect	960 ms	55656 KB	Output isn't correct
79	Incorrect	952 ms	55632 KB	Output isn't correct
80	Incorrect	961 ms	55632 KB	Output isn't correct
81	Incorrect	962 ms	55656 KB	Output isn't correct
82	Incorrect	955 ms	55656 KB	Output isn't correct
83	Incorrect	954 ms	55652 KB	Output isn't correct
84	Incorrect	965 ms	55656 KB	Output isn't correct
85	Incorrect	953 ms	55768 KB	Output isn't correct
86	Correct	951 ms	55656 KB	Output is correct
87	Correct	959 ms	55892 KB	Output is correct
88	Incorrect	960 ms	55656 KB	Output isn't correct
89	Incorrect	953 ms	55656 KB	Output isn't correct
90	Incorrect	955 ms	49864 KB	Output isn't correct
91	Incorrect	964 ms	55720 KB	Output isn't correct
92	Incorrect	971 ms	55656 KB	Output isn't correct
93	Incorrect	965 ms	55636 KB	Output isn't correct
94	Incorrect	960 ms	55652 KB	Output isn't correct
95	Incorrect	955 ms	55660 KB	Output isn't correct
96	Incorrect	960 ms	55652 KB	Output isn't correct
97	Incorrect	962 ms	55660 KB	Output isn't correct
98	Incorrect	957 ms	55892 KB	Output isn't correct
99	Incorrect	956 ms	55656 KB	Output isn't correct
100	Correct	963 ms	55660 KB	Output is correct