| # |
Submission time |
Handle |
Problem |
Language |
Result |
Execution time |
Memory |
| 404591 |
2021-05-14T17:15:45 Z |
rama_pang |
Bomb (IZhO17_bomb) |
C++17 |
|
512 ms |
73972 KB |
#include <bits/stdc++.h>
using namespace std;
int N, M;
int A[2505][2505];
int up[2505][2505];
int dn[2505][2505];
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin >> N >> M;
for (int i = 1; i <= N; i++) {
for (int j = 1; j <= M; j++) {
char c;
cin >> c;
A[i][j] = c - '0';
}
}
// Solution:
//
// The upper bound on height and width is the minimum length
// vertical and horizontal strip. Now, for a fixed width Y,
// we want to determine the maximum height X. Note that,
// if we have width Y, then for every maximal horizontal
// strip, height is bounded by the minimum (top - bottom)
// of the prefix and suffix of size Y.
//
// We only need to consider the prefix and suffix. Why?
// For, after a prefix of size Y, let's move it to the right.
// If the (top - bottom) decreased, that means that there is
// a vertical strip which is shifted downwards, which means
// it will occcupy a maximal horizontal strip -> we will compute
// it later.
//
// Time complexity: O(N M).
for (int j = 1; j <= M; j++) {
for (int i = 1; i <= N; i++) {
if (A[i][j]) {
up[i][j] = 1 + up[i - 1][j];
}
}
for (int i = N; i >= 1; i--) {
if (A[i][j]) {
dn[i][j] = 1 + dn[i + 1][j];
}
}
}
vector<int> ans(M + 2, N);
for (int rep = 0; rep < 2; rep++) { // for prefix, then suffix
for (int i = 1; i <= N; i++) {
for (int j = 1; j <= M; j++) if (A[i][j]) {
ans[1] = min(ans[1], up[i][j] + dn[i][j] - 1);
}
for (int j = 1; j <= M; j++) if (A[i][j] && !A[i][j - 1]) {
int jj = j;
while (A[i][jj + 1]) jj += 1;
int len = jj - j + 1;
int minUp = N;
int minDn = N;
for (int k = 1; k <= len; k++) {
minUp = min(minUp, up[i][j + k - 1]);
minDn = min(minDn, dn[i][j + k - 1]);
ans[k] = min(ans[k], minUp + minDn - 1);
}
ans[len + 1] = 0;
}
}
for (int i = 1; i <= N; i++) {
for (int j = 1; j + j <= M; j++) {
swap(A[i][j], A[i][M - j + 1]);
swap(up[i][j], up[i][M - j + 1]);
swap(dn[i][j], dn[i][M - j + 1]);
}
}
}
int answer = 0;
for (int i = 1; i <= M; i++) {
ans[i] = min(ans[i], ans[i - 1]);
answer = max(answer, i * ans[i]);
}
cout << answer << '\n';
return 0;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
332 KB |
Output is correct |
| 2 |
Correct |
1 ms |
460 KB |
Output is correct |
| 3 |
Correct |
14 ms |
30412 KB |
Output is correct |
| 4 |
Correct |
14 ms |
30420 KB |
Output is correct |
| 5 |
Correct |
1 ms |
332 KB |
Output is correct |
| 6 |
Correct |
1 ms |
332 KB |
Output is correct |
| 7 |
Correct |
1 ms |
332 KB |
Output is correct |
| 8 |
Correct |
1 ms |
460 KB |
Output is correct |
| 9 |
Correct |
1 ms |
460 KB |
Output is correct |
| 10 |
Correct |
1 ms |
460 KB |
Output is correct |
| 11 |
Correct |
1 ms |
460 KB |
Output is correct |
| 12 |
Correct |
1 ms |
460 KB |
Output is correct |
| 13 |
Correct |
1 ms |
460 KB |
Output is correct |
| 14 |
Correct |
1 ms |
460 KB |
Output is correct |
| 15 |
Correct |
1 ms |
460 KB |
Output is correct |
| 16 |
Correct |
1 ms |
460 KB |
Output is correct |
| 17 |
Correct |
2 ms |
1100 KB |
Output is correct |
| 18 |
Correct |
1 ms |
1228 KB |
Output is correct |
| 19 |
Correct |
2 ms |
1484 KB |
Output is correct |
| 20 |
Correct |
2 ms |
1484 KB |
Output is correct |
| 21 |
Correct |
1 ms |
972 KB |
Output is correct |
| 22 |
Correct |
2 ms |
1228 KB |
Output is correct |
| 23 |
Correct |
2 ms |
1612 KB |
Output is correct |
| 24 |
Correct |
1 ms |
1356 KB |
Output is correct |
| 25 |
Correct |
2 ms |
1612 KB |
Output is correct |
| 26 |
Correct |
2 ms |
1612 KB |
Output is correct |
| 27 |
Correct |
6 ms |
4772 KB |
Output is correct |
| 28 |
Correct |
6 ms |
5068 KB |
Output is correct |
| 29 |
Correct |
9 ms |
6476 KB |
Output is correct |
| 30 |
Correct |
10 ms |
7628 KB |
Output is correct |
| 31 |
Correct |
8 ms |
6092 KB |
Output is correct |
| 32 |
Correct |
8 ms |
6976 KB |
Output is correct |
| 33 |
Correct |
11 ms |
8136 KB |
Output is correct |
| 34 |
Correct |
6 ms |
5580 KB |
Output is correct |
| 35 |
Correct |
10 ms |
8012 KB |
Output is correct |
| 36 |
Correct |
14 ms |
8036 KB |
Output is correct |
| 37 |
Correct |
1 ms |
460 KB |
Output is correct |
| 38 |
Correct |
469 ms |
73828 KB |
Output is correct |
| 39 |
Correct |
1 ms |
460 KB |
Output is correct |
| 40 |
Correct |
57 ms |
19908 KB |
Output is correct |
| 41 |
Correct |
1 ms |
460 KB |
Output is correct |
| 42 |
Correct |
2 ms |
1636 KB |
Output is correct |
| 43 |
Correct |
419 ms |
73864 KB |
Output is correct |
| 44 |
Correct |
12 ms |
8032 KB |
Output is correct |
| 45 |
Correct |
418 ms |
73944 KB |
Output is correct |
| 46 |
Correct |
393 ms |
73848 KB |
Output is correct |
| 47 |
Correct |
421 ms |
73924 KB |
Output is correct |
| 48 |
Correct |
380 ms |
73940 KB |
Output is correct |
| 49 |
Correct |
490 ms |
73788 KB |
Output is correct |
| 50 |
Correct |
393 ms |
73844 KB |
Output is correct |
| 51 |
Correct |
386 ms |
73836 KB |
Output is correct |
| 52 |
Correct |
393 ms |
73796 KB |
Output is correct |
| 53 |
Correct |
380 ms |
73812 KB |
Output is correct |
| 54 |
Correct |
332 ms |
73856 KB |
Output is correct |
| 55 |
Correct |
325 ms |
73852 KB |
Output is correct |
| 56 |
Correct |
493 ms |
73764 KB |
Output is correct |
| 57 |
Correct |
333 ms |
73816 KB |
Output is correct |
| 58 |
Correct |
338 ms |
73852 KB |
Output is correct |
| 59 |
Correct |
329 ms |
73796 KB |
Output is correct |
| 60 |
Correct |
388 ms |
73888 KB |
Output is correct |
| 61 |
Correct |
495 ms |
73796 KB |
Output is correct |
| 62 |
Correct |
512 ms |
73852 KB |
Output is correct |
| 63 |
Correct |
509 ms |
73900 KB |
Output is correct |
| 64 |
Correct |
328 ms |
73872 KB |
Output is correct |
| 65 |
Correct |
381 ms |
73820 KB |
Output is correct |
| 66 |
Correct |
395 ms |
73828 KB |
Output is correct |
| 67 |
Correct |
396 ms |
73848 KB |
Output is correct |
| 68 |
Correct |
421 ms |
73876 KB |
Output is correct |
| 69 |
Correct |
336 ms |
73880 KB |
Output is correct |
| 70 |
Correct |
183 ms |
59224 KB |
Output is correct |
| 71 |
Correct |
364 ms |
73796 KB |
Output is correct |
| 72 |
Correct |
329 ms |
73856 KB |
Output is correct |
| 73 |
Correct |
336 ms |
73744 KB |
Output is correct |
| 74 |
Correct |
319 ms |
73796 KB |
Output is correct |
| 75 |
Correct |
338 ms |
73784 KB |
Output is correct |
| 76 |
Correct |
333 ms |
73776 KB |
Output is correct |
| 77 |
Correct |
339 ms |
73852 KB |
Output is correct |
| 78 |
Correct |
330 ms |
73848 KB |
Output is correct |
| 79 |
Correct |
270 ms |
73896 KB |
Output is correct |
| 80 |
Correct |
308 ms |
73792 KB |
Output is correct |
| 81 |
Correct |
276 ms |
73812 KB |
Output is correct |
| 82 |
Correct |
339 ms |
73836 KB |
Output is correct |
| 83 |
Correct |
343 ms |
73828 KB |
Output is correct |
| 84 |
Correct |
279 ms |
73852 KB |
Output is correct |
| 85 |
Correct |
344 ms |
73796 KB |
Output is correct |
| 86 |
Correct |
458 ms |
73804 KB |
Output is correct |
| 87 |
Correct |
328 ms |
73748 KB |
Output is correct |
| 88 |
Correct |
332 ms |
73728 KB |
Output is correct |
| 89 |
Correct |
375 ms |
73796 KB |
Output is correct |
| 90 |
Correct |
206 ms |
59232 KB |
Output is correct |
| 91 |
Correct |
347 ms |
73796 KB |
Output is correct |
| 92 |
Correct |
364 ms |
73840 KB |
Output is correct |
| 93 |
Correct |
462 ms |
73952 KB |
Output is correct |
| 94 |
Correct |
383 ms |
73752 KB |
Output is correct |
| 95 |
Correct |
342 ms |
73836 KB |
Output is correct |
| 96 |
Correct |
346 ms |
73840 KB |
Output is correct |
| 97 |
Correct |
471 ms |
73972 KB |
Output is correct |
| 98 |
Correct |
342 ms |
73768 KB |
Output is correct |
| 99 |
Correct |
366 ms |
73852 KB |
Output is correct |
| 100 |
Correct |
481 ms |
73764 KB |
Output is correct |
