#include <bits/stdc++.h>
using namespace std;
const int N = 2500;
int arr[N][N];
int pref[N][N];
class segment_tree {
public:
segment_tree() {
}
segment_tree(size_t s) {
n = 1;
while (n < s) n <<= 1;
t.assign(2 * n, 0);
lazy = t;
}
void push(int v, int vl, int vr) {
if (vl == vr || lazy[v] == -1) return;
lazy[v << 1] = lazy[v];
lazy[v << 1 | 1] = lazy[v];
int vm = vl + vr >> 1;
t[v << 1] = lazy[v] * (vm - vl + 1);
t[v << 1 | 1] = lazy[v] * (vr - vm);
lazy[v] = -1;
}
void update(int l, int r, int x, int v, int vl, int vr) {
push(v, vl, vr);
if (l > vr || vl > r) return;
if (l <= vl && vr <= r) {
t[v] = x * (vr - vl + 1);
lazy[v] = x;
return;
}
int vm = vl + vr >> 1;
update(l, r, x, v << 1, vl, vm);
update(l, r, x, v << 1 | 1, vm + 1, vr);
t[v] = t[v << 1] + t[v << 1 | 1];
}
void update(int l, int r, int x) {
update(l, r, x, 1, 0, n - 1);
}
int query(int l, int r, int v, int vl, int vr) {
push(v, vl, vr);
if (l > vr || vl > r) return 0;
if (l <= vl && vr <= r) return t[v];
int vm = vl + vr >> 1;
int q1 = query(l, r, v << 1, vl, vm);
int q2 = query(l, r, v << 1 | 1, vm + 1, vr);
t[v] = t[v << 1] + t[v << 1 | 1];
return q1 + q2;
}
int query(int l, int r) {
return query(l, r, 1, 0, n - 1);
}
private:
int n;
vector<int> t, lazy;
};
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
int n, m;
cin >> n >> m;
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
char x; cin >> x;
arr[i][j] = x - '0';
}
}
if (n > m) {
int brr[m][n];
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
brr[i][j] = arr[j][i];
}
}
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
arr[i][j] = brr[i][j];
}
}
swap(n, m);
}
vector<segment_tree> st(n);
for (int i = 0; i < n; i++)
st[i] = segment_tree(m);
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
st[i].update(j, j, arr[i][j]);
pref[i][j] = arr[i][j];
pref[i][j] += (i ? pref[i - 1][j] : 0);
pref[i][j] += (j ? pref[i][j - 1] : 0);
pref[i][j] -= (i && j ? pref[i - 1][j - 1] : 0);
}
}
auto get = [&](int a, int b, int c, int d) ->int {
int s = pref[c][d];
s -= (a ? pref[a - 1][d] : 0);
s -= (b ? pref[c][b - 1] : 0);
s += (a && b ? pref[a - 1][b - 1] : 0);
return s;
};
// brute force
int Q = 2;
auto check = [&](int a, int b) ->int {
for (int i = 0; i + a - 1 < n; i++) {
for (int j = 0; j + b - 1 < m; j++) {
int g = get(i, j, i + a - 1, j + b - 1);
if (g == a * b) {
for (int x = i; x <= i + a - 1; x++) {
st[x].update(j, j + b - 1, Q);
}
}
}
}
int ok = 1;
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
if (st[i].query(j, j) != 0 && st[i].query(j, j) != Q)
ok = 0;
}
}
Q++;
return ok;
};
//O(n*n * 12*m * 12*12)
//O(10000 *120 * 144)
//O(1000000)
int ans = 0;
for (int a = 1; a <= n; a++) {
int l = 1, r = m;
while (l < r) {
int b = (l + r + 1) / 2;
if (check(a, b))
l = b;
else
r = b - 1;
}
if (check(a, l))
ans = max(ans, a * l);
}
cout << ans << '\n';
return 0;
}
Compilation message
bomb.cpp: In constructor 'segment_tree::segment_tree(size_t)':
bomb.cpp:15:12: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare]
15 | while (n < s) n <<= 1;
| ~~^~~
bomb.cpp: In member function 'void segment_tree::push(int, int, int)':
bomb.cpp:23:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
23 | int vm = vl + vr >> 1;
| ~~~^~~~
bomb.cpp: In member function 'void segment_tree::update(int, int, int, int, int, int)':
bomb.cpp:36:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
36 | int vm = vl + vr >> 1;
| ~~~^~~~
bomb.cpp: In member function 'int segment_tree::query(int, int, int, int, int)':
bomb.cpp:48:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
48 | int vm = vl + vr >> 1;
| ~~~^~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
204 KB |
Output is correct |
2 |
Correct |
0 ms |
332 KB |
Output is correct |
3 |
Correct |
18 ms |
10448 KB |
Output is correct |
4 |
Correct |
18 ms |
10440 KB |
Output is correct |
5 |
Correct |
11 ms |
332 KB |
Output is correct |
6 |
Correct |
4 ms |
332 KB |
Output is correct |
7 |
Correct |
1 ms |
332 KB |
Output is correct |
8 |
Correct |
2 ms |
460 KB |
Output is correct |
9 |
Correct |
3 ms |
460 KB |
Output is correct |
10 |
Correct |
1 ms |
332 KB |
Output is correct |
11 |
Correct |
2 ms |
460 KB |
Output is correct |
12 |
Correct |
1 ms |
332 KB |
Output is correct |
13 |
Correct |
1 ms |
332 KB |
Output is correct |
14 |
Correct |
2 ms |
332 KB |
Output is correct |
15 |
Correct |
2 ms |
472 KB |
Output is correct |
16 |
Correct |
7 ms |
496 KB |
Output is correct |
17 |
Correct |
166 ms |
992 KB |
Output is correct |
18 |
Correct |
108 ms |
1008 KB |
Output is correct |
19 |
Correct |
262 ms |
1244 KB |
Output is correct |
20 |
Correct |
303 ms |
1272 KB |
Output is correct |
21 |
Correct |
96 ms |
880 KB |
Output is correct |
22 |
Correct |
207 ms |
1124 KB |
Output is correct |
23 |
Correct |
586 ms |
1388 KB |
Output is correct |
24 |
Correct |
221 ms |
1100 KB |
Output is correct |
25 |
Correct |
879 ms |
1384 KB |
Output is correct |
26 |
Execution timed out |
1090 ms |
1356 KB |
Time limit exceeded |
27 |
Execution timed out |
1026 ms |
5580 KB |
Time limit exceeded |
28 |
Execution timed out |
1091 ms |
5776 KB |
Time limit exceeded |
29 |
Execution timed out |
1068 ms |
7244 KB |
Time limit exceeded |
30 |
Execution timed out |
1091 ms |
8644 KB |
Time limit exceeded |
31 |
Execution timed out |
1041 ms |
6852 KB |
Time limit exceeded |
32 |
Execution timed out |
1082 ms |
8388 KB |
Time limit exceeded |
33 |
Execution timed out |
1090 ms |
9036 KB |
Time limit exceeded |
34 |
Execution timed out |
1084 ms |
5580 KB |
Time limit exceeded |
35 |
Execution timed out |
1089 ms |
9060 KB |
Time limit exceeded |
36 |
Execution timed out |
1084 ms |
9028 KB |
Time limit exceeded |
37 |
Correct |
3 ms |
460 KB |
Output is correct |
38 |
Runtime error |
131 ms |
131076 KB |
Execution killed with signal 9 |
39 |
Correct |
4 ms |
460 KB |
Output is correct |
40 |
Execution timed out |
1092 ms |
27424 KB |
Time limit exceeded |
41 |
Correct |
5 ms |
460 KB |
Output is correct |
42 |
Execution timed out |
1083 ms |
1356 KB |
Time limit exceeded |
43 |
Runtime error |
138 ms |
131076 KB |
Execution killed with signal 9 |
44 |
Execution timed out |
1095 ms |
9036 KB |
Time limit exceeded |
45 |
Runtime error |
139 ms |
131076 KB |
Execution killed with signal 9 |
46 |
Runtime error |
134 ms |
131076 KB |
Execution killed with signal 9 |
47 |
Runtime error |
140 ms |
131076 KB |
Execution killed with signal 9 |
48 |
Runtime error |
134 ms |
131076 KB |
Execution killed with signal 9 |
49 |
Runtime error |
144 ms |
131076 KB |
Execution killed with signal 9 |
50 |
Runtime error |
137 ms |
131076 KB |
Execution killed with signal 9 |
51 |
Runtime error |
137 ms |
131076 KB |
Execution killed with signal 9 |
52 |
Runtime error |
156 ms |
131076 KB |
Execution killed with signal 9 |
53 |
Runtime error |
137 ms |
131076 KB |
Execution killed with signal 9 |
54 |
Runtime error |
136 ms |
131076 KB |
Execution killed with signal 9 |
55 |
Runtime error |
136 ms |
131076 KB |
Execution killed with signal 9 |
56 |
Runtime error |
132 ms |
131076 KB |
Execution killed with signal 9 |
57 |
Runtime error |
137 ms |
131076 KB |
Execution killed with signal 9 |
58 |
Runtime error |
140 ms |
131076 KB |
Execution killed with signal 9 |
59 |
Runtime error |
146 ms |
131192 KB |
Execution killed with signal 9 |
60 |
Runtime error |
134 ms |
131076 KB |
Execution killed with signal 9 |
61 |
Runtime error |
142 ms |
131076 KB |
Execution killed with signal 9 |
62 |
Runtime error |
131 ms |
131076 KB |
Execution killed with signal 9 |
63 |
Runtime error |
145 ms |
131076 KB |
Execution killed with signal 9 |
64 |
Runtime error |
134 ms |
131076 KB |
Execution killed with signal 9 |
65 |
Runtime error |
133 ms |
131076 KB |
Execution killed with signal 9 |
66 |
Runtime error |
153 ms |
131076 KB |
Execution killed with signal 9 |
67 |
Runtime error |
137 ms |
131076 KB |
Execution killed with signal 9 |
68 |
Runtime error |
136 ms |
131076 KB |
Execution killed with signal 9 |
69 |
Runtime error |
139 ms |
131076 KB |
Execution killed with signal 9 |
70 |
Execution timed out |
1104 ms |
103748 KB |
Time limit exceeded |
71 |
Runtime error |
142 ms |
131076 KB |
Execution killed with signal 9 |
72 |
Runtime error |
141 ms |
131076 KB |
Execution killed with signal 9 |
73 |
Runtime error |
150 ms |
131076 KB |
Execution killed with signal 9 |
74 |
Runtime error |
142 ms |
131076 KB |
Execution killed with signal 9 |
75 |
Runtime error |
163 ms |
131076 KB |
Execution killed with signal 9 |
76 |
Runtime error |
140 ms |
131076 KB |
Execution killed with signal 9 |
77 |
Runtime error |
133 ms |
131076 KB |
Execution killed with signal 9 |
78 |
Runtime error |
134 ms |
131076 KB |
Execution killed with signal 9 |
79 |
Runtime error |
137 ms |
131076 KB |
Execution killed with signal 9 |
80 |
Runtime error |
133 ms |
131076 KB |
Execution killed with signal 9 |
81 |
Runtime error |
137 ms |
131076 KB |
Execution killed with signal 9 |
82 |
Runtime error |
133 ms |
131076 KB |
Execution killed with signal 9 |
83 |
Runtime error |
161 ms |
131076 KB |
Execution killed with signal 9 |
84 |
Runtime error |
134 ms |
131076 KB |
Execution killed with signal 9 |
85 |
Runtime error |
137 ms |
131076 KB |
Execution killed with signal 9 |
86 |
Runtime error |
136 ms |
131076 KB |
Execution killed with signal 9 |
87 |
Runtime error |
139 ms |
131076 KB |
Execution killed with signal 9 |
88 |
Runtime error |
142 ms |
131076 KB |
Execution killed with signal 9 |
89 |
Runtime error |
135 ms |
131076 KB |
Execution killed with signal 9 |
90 |
Execution timed out |
1095 ms |
103772 KB |
Time limit exceeded |
91 |
Runtime error |
141 ms |
131076 KB |
Execution killed with signal 9 |
92 |
Runtime error |
139 ms |
131076 KB |
Execution killed with signal 9 |
93 |
Runtime error |
139 ms |
131076 KB |
Execution killed with signal 9 |
94 |
Runtime error |
135 ms |
131076 KB |
Execution killed with signal 9 |
95 |
Runtime error |
135 ms |
131076 KB |
Execution killed with signal 9 |
96 |
Runtime error |
152 ms |
131076 KB |
Execution killed with signal 9 |
97 |
Runtime error |
133 ms |
131076 KB |
Execution killed with signal 9 |
98 |
Runtime error |
142 ms |
131076 KB |
Execution killed with signal 9 |
99 |
Runtime error |
136 ms |
131076 KB |
Execution killed with signal 9 |
100 |
Runtime error |
131 ms |
131076 KB |
Execution killed with signal 9 |