#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++){
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;
}
| # |
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 |
10 ms |
54436 KB |
Output is correct |
| 4 |
Correct |
10 ms |
54616 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 |
4488 KB |
Output is correct |
| 10 |
Correct |
1 ms |
4440 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 |
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 |
2 ms |
6900 KB |
Output is correct |
| 17 |
Correct |
3 ms |
9204 KB |
Output is correct |
| 18 |
Correct |
2 ms |
8796 KB |
Output is correct |
| 19 |
Correct |
2 ms |
10844 KB |
Output is correct |
| 20 |
Correct |
2 ms |
10844 KB |
Output is correct |
| 21 |
Correct |
1 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 |
10840 KB |
Output is correct |
| 25 |
Correct |
4 ms |
10844 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 |
14940 KB |
Output is correct |
| 29 |
Correct |
52 ms |
14940 KB |
Output is correct |
| 30 |
Correct |
130 ms |
14940 KB |
Output is correct |
| 31 |
Correct |
77 ms |
14988 KB |
Output is correct |
| 32 |
Correct |
86 ms |
14940 KB |
Output is correct |
| 33 |
Correct |
169 ms |
16988 KB |
Output is correct |
| 34 |
Correct |
7 ms |
13400 KB |
Output is correct |
| 35 |
Correct |
49 ms |
16988 KB |
Output is correct |
| 36 |
Correct |
51 ms |
19084 KB |
Output is correct |
| 37 |
Correct |
1 ms |
6488 KB |
Output is correct |
| 38 |
Correct |
966 ms |
55660 KB |
Output is correct |
| 39 |
Correct |
1 ms |
6488 KB |
Output is correct |
| 40 |
Correct |
950 ms |
27300 KB |
Output is correct |
| 41 |
Correct |
1 ms |
6488 KB |
Output is correct |
| 42 |
Correct |
5 ms |
10844 KB |
Output is correct |
| 43 |
Correct |
961 ms |
55832 KB |
Output is correct |
| 44 |
Correct |
233 ms |
19032 KB |
Output is correct |
| 45 |
Incorrect |
973 ms |
55708 KB |
Output isn't correct |
| 46 |
Correct |
965 ms |
55656 KB |
Output is correct |
| 47 |
Incorrect |
974 ms |
55660 KB |
Output isn't correct |
| 48 |
Correct |
978 ms |
55636 KB |
Output is correct |
| 49 |
Correct |
434 ms |
55656 KB |
Output is correct |
| 50 |
Correct |
951 ms |
55660 KB |
Output is correct |
| 51 |
Correct |
958 ms |
55656 KB |
Output is correct |
| 52 |
Correct |
965 ms |
55660 KB |
Output is correct |
| 53 |
Correct |
977 ms |
55888 KB |
Output is correct |
| 54 |
Correct |
951 ms |
55656 KB |
Output is correct |
| 55 |
Correct |
960 ms |
55828 KB |
Output is correct |
| 56 |
Correct |
961 ms |
55680 KB |
Output is correct |
| 57 |
Correct |
957 ms |
55652 KB |
Output is correct |
| 58 |
Correct |
958 ms |
55656 KB |
Output is correct |
| 59 |
Correct |
964 ms |
55652 KB |
Output is correct |
| 60 |
Correct |
960 ms |
55652 KB |
Output is correct |
| 61 |
Correct |
871 ms |
55864 KB |
Output is correct |
| 62 |
Correct |
956 ms |
55720 KB |
Output is correct |
| 63 |
Correct |
974 ms |
55656 KB |
Output is correct |
| 64 |
Correct |
957 ms |
55892 KB |
Output is correct |
| 65 |
Correct |
955 ms |
55652 KB |
Output is correct |
| 66 |
Correct |
721 ms |
55656 KB |
Output is correct |
| 67 |
Correct |
975 ms |
55656 KB |
Output is correct |
| 68 |
Correct |
969 ms |
55636 KB |
Output is correct |
| 69 |
Correct |
976 ms |
55632 KB |
Output is correct |
| 70 |
Incorrect |
950 ms |
49868 KB |
Output isn't correct |
| 71 |
Incorrect |
962 ms |
55456 KB |
Output isn't correct |
| 72 |
Incorrect |
963 ms |
55888 KB |
Output isn't correct |
| 73 |
Incorrect |
963 ms |
55656 KB |
Output isn't correct |
| 74 |
Incorrect |
967 ms |
55656 KB |
Output isn't correct |
| 75 |
Incorrect |
952 ms |
55652 KB |
Output isn't correct |
| 76 |
Incorrect |
963 ms |
55656 KB |
Output isn't correct |
| 77 |
Incorrect |
959 ms |
55656 KB |
Output isn't correct |
| 78 |
Incorrect |
960 ms |
55660 KB |
Output isn't correct |
| 79 |
Incorrect |
974 ms |
55692 KB |
Output isn't correct |
| 80 |
Incorrect |
964 ms |
55656 KB |
Output isn't correct |
| 81 |
Incorrect |
957 ms |
55660 KB |
Output isn't correct |
| 82 |
Incorrect |
964 ms |
55656 KB |
Output isn't correct |
| 83 |
Incorrect |
968 ms |
55660 KB |
Output isn't correct |
| 84 |
Incorrect |
956 ms |
55660 KB |
Output isn't correct |
| 85 |
Incorrect |
958 ms |
55656 KB |
Output isn't correct |
| 86 |
Correct |
952 ms |
55656 KB |
Output is correct |
| 87 |
Correct |
956 ms |
55636 KB |
Output is correct |
| 88 |
Incorrect |
960 ms |
55656 KB |
Output isn't correct |
| 89 |
Incorrect |
961 ms |
55656 KB |
Output isn't correct |
| 90 |
Incorrect |
961 ms |
49868 KB |
Output isn't correct |
| 91 |
Incorrect |
964 ms |
55656 KB |
Output isn't correct |
| 92 |
Incorrect |
977 ms |
55660 KB |
Output isn't correct |
| 93 |
Incorrect |
971 ms |
55660 KB |
Output isn't correct |
| 94 |
Incorrect |
963 ms |
55652 KB |
Output isn't correct |
| 95 |
Incorrect |
955 ms |
55656 KB |
Output isn't correct |
| 96 |
Incorrect |
966 ms |
55652 KB |
Output isn't correct |
| 97 |
Incorrect |
978 ms |
55656 KB |
Output isn't correct |
| 98 |
Incorrect |
959 ms |
55656 KB |
Output isn't correct |
| 99 |
Incorrect |
958 ms |
55456 KB |
Output isn't correct |
| 100 |
Correct |
951 ms |
55656 KB |
Output is correct |
