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Submission #907307

# Submission time Handle Problem Language Result Execution time Memory
907307 2024-01-15T11:12:48 Z daoquanglinh2007 Bomb (IZhO17_bomb) C++17
43 / 100
 1000 ms 55888 KB 
#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];

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

int get_rand(int l, int r){
	int tmp = rng()%(r-l+1);
	if (tmp < 0) tmp += r-l+1;
	return l + tmp;
}
 
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;
		}
}

void solve(int h){
	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;
		}
	}
}
 
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;
	}
			
	solve(H);
	for (int i = 1; i <= 5; i++){
		int h = get_rand(1, H);
		solve(h);
	}
	cout << ans;
	return 0;
}

Subtask #1
43.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Correct 2 ms 6492 KB Output is correct
3 Correct 10 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 6492 KB Output is correct
9 Correct 1 ms 6488 KB Output is correct
10 Correct 1 ms 4444 KB Output is correct
11 Correct 1 ms 6492 KB Output is correct
12 Correct 1 ms 4440 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 10844 KB Output is correct
23 Correct 4 ms 10844 KB Output is correct
24 Correct 3 ms 10892 KB Output is correct
25 Correct 4 ms 10896 KB Output is correct
26 Correct 3 ms 10844 KB Output is correct
27 Correct 4 ms 15192 KB Output is correct
28 Correct 8 ms 13148 KB Output is correct
29 Correct 52 ms 14940 KB Output is correct
30 Correct 134 ms 14940 KB Output is correct
31 Correct 81 ms 13404 KB Output is correct
32 Correct 90 ms 14976 KB Output is correct
33 Correct 173 ms 17156 KB Output is correct
34 Correct 7 ms 13400 KB Output is correct
35 Correct 59 ms 16224 KB Output is correct
36 Correct 52 ms 19036 KB Output is correct
37 Correct 2 ms 6492 KB Output is correct
38 Execution timed out 1088 ms 55708 KB Time limit exceeded
39 Correct 1 ms 6488 KB Output is correct
40 Incorrect 131 ms 27292 KB Output isn't correct
41 Correct 2 ms 6488 KB Output is correct
42 Correct 5 ms 10844 KB Output is correct
43 Execution timed out 1059 ms 55452 KB Time limit exceeded
44 Correct 244 ms 19284 KB Output is correct
45 Execution timed out 1073 ms 55452 KB Time limit exceeded
46 Correct 914 ms 55440 KB Output is correct
47 Execution timed out 1067 ms 55636 KB Time limit exceeded
48 Execution timed out 1058 ms 55620 KB Time limit exceeded
49 Correct 607 ms 55872 KB Output is correct
50 Execution timed out 1018 ms 55632 KB Time limit exceeded
51 Execution timed out 1026 ms 55428 KB Time limit exceeded
52 Execution timed out 1024 ms 55440 KB Time limit exceeded
53 Execution timed out 1066 ms 55636 KB Time limit exceeded
54 Execution timed out 1099 ms 55632 KB Time limit exceeded
55 Execution timed out 1025 ms 55632 KB Time limit exceeded
56 Execution timed out 1018 ms 55664 KB Time limit exceeded
57 Execution timed out 1026 ms 55456 KB Time limit exceeded
58 Execution timed out 1070 ms 55452 KB Time limit exceeded
59 Execution timed out 1076 ms 55440 KB Time limit exceeded
60 Execution timed out 1010 ms 55656 KB Time limit exceeded
61 Execution timed out 1010 ms 55660 KB Time limit exceeded
62 Execution timed out 1025 ms 55632 KB Time limit exceeded
63 Execution timed out 1053 ms 55636 KB Time limit exceeded
64 Execution timed out 1041 ms 55820 KB Time limit exceeded
65 Execution timed out 1034 ms 55656 KB Time limit exceeded
66 Execution timed out 1039 ms 55432 KB Time limit exceeded
67 Execution timed out 1094 ms 55636 KB Time limit exceeded
68 Execution timed out 1033 ms 55612 KB Time limit exceeded
69 Execution timed out 1080 ms 55448 KB Time limit exceeded
70 Incorrect 708 ms 49864 KB Output isn't correct
71 Incorrect 901 ms 55664 KB Output isn't correct
72 Execution timed out 1078 ms 55448 KB Time limit exceeded
73 Execution timed out 1072 ms 55636 KB Time limit exceeded
74 Execution timed out 1067 ms 55664 KB Time limit exceeded
75 Execution timed out 1024 ms 55444 KB Time limit exceeded
76 Execution timed out 1020 ms 55632 KB Time limit exceeded
77 Incorrect 951 ms 55656 KB Output isn't correct
78 Execution timed out 1044 ms 55660 KB Time limit exceeded
79 Incorrect 556 ms 55660 KB Output isn't correct
80 Incorrect 543 ms 55664 KB Output isn't correct
81 Incorrect 906 ms 55656 KB Output isn't correct
82 Incorrect 950 ms 55664 KB Output isn't correct
83 Execution timed out 1073 ms 55428 KB Time limit exceeded
84 Incorrect 662 ms 55668 KB Output isn't correct
85 Execution timed out 1012 ms 55660 KB Time limit exceeded
86 Incorrect 639 ms 55660 KB Output isn't correct
87 Execution timed out 1081 ms 55660 KB Time limit exceeded
88 Execution timed out 1094 ms 55440 KB Time limit exceeded
89 Execution timed out 1041 ms 55888 KB Time limit exceeded
90 Incorrect 630 ms 49744 KB Output isn't correct
91 Incorrect 855 ms 55888 KB Output isn't correct
92 Incorrect 875 ms 55656 KB Output isn't correct
93 Incorrect 667 ms 55656 KB Output isn't correct
94 Incorrect 966 ms 55664 KB Output isn't correct
95 Execution timed out 1008 ms 55460 KB Time limit exceeded
96 Execution timed out 1064 ms 55636 KB Time limit exceeded
97 Incorrect 817 ms 55660 KB Output isn't correct
98 Execution timed out 1016 ms 55792 KB Time limit exceeded
99 Execution timed out 1018 ms 55632 KB Time limit exceeded
100 Incorrect 630 ms 55676 KB Output isn't correct