CSES - IZhO 2017, day 2 - Results
Submission details
Task:Bomb
Sender:Yytsi
Submission time:2019-02-05 16:59:47 +0200
Language:C++
Status:READY
Result:43
Feedback
groupverdictscore
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Test results
testverdicttimegroup
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Code

#include <bits/stdc++.h>
using namespace std;
#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define IO ios_base::sync_with_stdio(0); cin.tie(0)
#define F first
#define S second
#define pb push_back
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define N 2505
bool A[N][N];
int dp[N][N];

int able[N][N], deto[N][N];

int n, m;

int rect(int y, int x, int w, int h) {
  // from (y, x) -> (y+h, w+h)
  return dp[y+h-1][x+w-1] - dp[y+h-1][x-1] - dp[y-1][x+w-1] + dp[y-1][x-1];
}

int det(int y, int x, int w, int h) {
  return deto[y+h-1][x+w-1] - deto[y+h-1][x-1] - deto[y-1][x+w-1] + deto[y-1][x-1];
}

bool ir(int y, int x) {
  return (1 <= y && y <= n) && (1 <= x && x <= m);
}

bool ok(int w, int h) {
  FOR(y,1,n+1) {
    FOR(x,1,m+1) {
      int ty = y+h-1, tx = x+w-1;
      if (!ir(ty, tx)) continue;
      able[y][x] = rect(y,x,w,h) == w*h;
    }
  }

  FOR(y,1,n+1) {
    FOR(x,1,m+1) {
      deto[y][x] = able[y][x]+deto[y-1][x]+deto[y][x-1]-deto[y-1][x-1];
    }
  }

  FOR(y,1,n+1) {
    FOR(x,1,m+1) {
      if (!A[y][x]) continue;
      // Check if this cell can be a part of some explosion
      int lx = x-w+1, ly = y-h+1;
      lx = max(1, lx);
      ly = max(1, ly);
      int wdiff = abs(x - lx) + 1;
      int hdiff = abs(y - ly) + 1;
      if (det(ly, lx, wdiff, hdiff) == 0) return false;
    }
  }

  return true;
}

int scanline(int y) {
  // Scan minimum constraint for width.
  int mn = 1e9;
  int c = 0;
  FOR(x,1,m+1) {
    if (A[y][x]) {
      c++;
    } else {
      if (c == 0) continue;
      mn = min(mn, c);
      c = 0;
    }
  }

  if (c != 0) mn = min(c, mn);

  return mn;
}

int scancol(int x) {
  // Scan minimum constraint for height.
  int mn = 1e9;
  int c = 0;
  FOR(y,1,n+1) {
    if (A[y][x]) {
      c++;
    } else {
      if (c == 0) continue;
      mn = min(mn, c);
      c = 0;
    }
  }

  if (c != 0) mn = min(c, mn);

  return mn;
}



int main() {
  IO; cin>>n>>m;
  FOR(y,1,n+1) {
    FOR(x,1,m+1) {
      char c; cin>>c;
      if (c == '1') A[y][x] = true;
      dp[y][x] = dp[y-1][x] + dp[y][x-1] - dp[y-1][x-1] + (int)A[y][x];
    }
  }

  int H = n, W = m;
  FOR(y,1,n+1) {
    int r = scanline(y);
    if (r == 1e9) continue;
    W = min(W, r);
  }

  FOR(x,1,n+1) {
    int r = scancol(x);
    if (r == 1e9) continue;
    H = min(H, r);
  }

  int ans = 0;
  FOR(x,1,H+1) {
    while (true) {
      bool r = ok(W, x);
      //cout<<x<<" "<<W<<" => "<<r<<"\n";
      if (!r) W--;
      else break;
    }
    ans = max(ans, x * W);
  }

  cout<<ans<<"\n";
}

Test details

Test 1

Group: 1

Verdict: ACCEPTED

input
1 20
00001111101110011110

correct output
3

user output
3

Test 2

Group: 2

Verdict: ACCEPTED

input
20 1
1
1
1
0
...

correct output
2

user output
2

Test 3

Group: 3

Verdict: ACCEPTED

input
2499 1
1
1
1
1
...

correct output
38

user output
38

Test 4

Group: 4

Verdict: ACCEPTED

input
2499 1
1
1
1
1
...

correct output
55

user output
55

Test 5

Group: 5

Verdict: ACCEPTED

input
1 2500
111111111110111111111110111111...

correct output
7

user output
7

Test 6

Group: 6

Verdict: ACCEPTED

input
1 1000
111111111111111111111111111111...

correct output
33

user output
33

Test 7

Group: 7

Verdict: ACCEPTED

input
5 5
11111
11111
11011
11111
...

correct output
4

user output
4

Test 8

Group: 8

Verdict: ACCEPTED

input
20 20
11111000000000000000
11111000000000000000
11111100000000000000
11111111111000000000
...

correct output
8

user output
8

Test 9

Group: 9

Verdict: ACCEPTED

input
20 20
11111100000000000000
11111100000000000000
11111110000000000000
11111111111110000000
...

correct output
12

user output
12

Test 10

Group: 10

Verdict: ACCEPTED

input
14 13
0000011100000
0000011100000
0000011100000
0000011110000
...

correct output
4

user output
4

Test 11

Group: 11

Verdict: ACCEPTED

input
20 19
1111110000000000000
1111111000000000000
1111111000000000000
1111111000000000000
...

correct output
10

user output
10

Test 12

Group: 12

Verdict: ACCEPTED

input
15 15
110000000000000
110000000000000
110000000000000
111000000000000
...

correct output
2

user output
2

Test 13

Group: 13

Verdict: ACCEPTED

input
15 11
00111000000
00111000000
00111000000
00111000000
...

correct output
3

user output
3

Test 14

Group: 14

Verdict: ACCEPTED

input
16 16
0000111100001111
0000111100001111
0000111100001111
0000111100001111
...

correct output
16

user output
16

Test 15

Group: 15

Verdict: ACCEPTED

input
18 18
111110000000000000
111110000000000000
111110000000000000
111111000000000000
...

correct output
8

user output
8

Test 16

Group: 16

Verdict: ACCEPTED

input
20 20
11111111111111011111
11111111111111011111
11111111111111011111
11111111111111111111
...

correct output
20

user output
20

Test 17

Group: 17

Verdict: ACCEPTED

input
65 70
000000000000000011111000000000...

correct output
15

user output
15

Test 18

Group: 18

Verdict: ACCEPTED

input
70 62
111100000000000000000000000000...

correct output
6

user output
6

Test 19

Group: 19

Verdict: ACCEPTED

input
94 78
111111111111111100000000000000...

correct output
22

user output
22

Test 20

Group: 20

Verdict: ACCEPTED

input
92 84
111111111111111110000000000000...

correct output
27

user output
27

Test 21

Group: 21

Verdict: ACCEPTED

input
53 89
000001111000000000000000000000...

correct output
6

user output
6

Test 22

Group: 22

Verdict: ACCEPTED

input
76 93
000011111100000000000000000000...

correct output
12

user output
12

Test 23

Group: 23

Verdict: ACCEPTED

input
100 100
111111111111111111111111111111...

correct output
209

user output
209

Test 24

Group: 24

Verdict: ACCEPTED

input
81 74
111111111111111110000000000000...

correct output
30

user output
30

Test 25

Group: 25

Verdict: ACCEPTED

input
100 100
111111111111111111111111111111...

correct output
80

user output
80

Test 26

Group: 26

Verdict: ACCEPTED

input
100 100
111111111111111111111111111111...

correct output
132

user output
132

Test 27

Group: 27

Verdict: ACCEPTED

input
295 268
111111111111111111111111111111...

correct output
3

user output
3

Test 28

Group: 28

Verdict: ACCEPTED

input
290 383
111111110000000000000000000000...

correct output
20

user output
20

Test 29

Group: 29

Verdict: ACCEPTED

input
390 320
000000000000000000000000000000...

correct output
3038

user output
3038

Test 30

Group: 30

Verdict: ACCEPTED

input
432 434
111111111111111111111111111111...

correct output
221

user output
221

Test 31

Group: 31

Verdict: ACCEPTED

input
334 450
111111111111111111111111111111...

correct output
391

user output
391

Test 32

Group: 32

Verdict: ACCEPTED

input
407 383
111111111111111111111111111111...

correct output
156

user output
156

Test 33

Group: 33

Verdict: ACCEPTED

input
450 450
111111111111111111111111111111...

correct output
1235

user output
1235

Test 34

Group: 34

Verdict: ACCEPTED

input
356 231
000000000001111111111110000000...

correct output
42

user output
42

Test 35

Group: 35

Verdict: ACCEPTED

input
450 450
111111111111111111111111111111...

correct output
192

user output
192

Test 36

Group: 36

Verdict: ACCEPTED

input
450 450
111111111111111111111111111111...

correct output
1404

user output
1404

Test 37

Group: 37

Verdict: ACCEPTED

input
20 20
00000000001111111111
00000000001111111111
00000000001111111111
00000000001111111111
...

correct output
14

user output
14

Test 38

Group: 38

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
6250000

user output
(empty)

Test 39

Group: 39

Verdict: ACCEPTED

input
20 20
00000000001111111111
00000000001111111111
00000000111111111111
00000001111111111111
...

correct output
24

user output
24

Test 40

Group: 40

Verdict:

input
875 882
111111111111111111111111111111...

correct output
69552

user output
(empty)

Test 41

Group: 41

Verdict: ACCEPTED

input
20 20
00000000111111111111
00000011111111111111
00000011111111111111
00000111111111111111
...

correct output
36

user output
36

Test 42

Group: 42

Verdict: ACCEPTED

input
100 100
000000000000000000000000000000...

correct output
651

user output
651

Test 43

Group: 43

Verdict:

input
2500 2500
000000000000000000000000000000...

correct output
250500

user output
(empty)

Test 44

Group: 44

Verdict: ACCEPTED

input
450 450
000000000000000000000000000000...

correct output
12864

user output
12864

Test 45

Group: 45

Verdict:

input
2500 2500
000000000000000000000000000000...

correct output
399456

user output
(empty)

Test 46

Group: 46

Verdict:

input
2500 2500
111111111111111111111111100000...

correct output
625

user output
(empty)

Test 47

Group: 47

Verdict:

input
2500 2500
000000000000000000000000000000...

correct output
395486

user output
(empty)

Test 48

Group: 48

Verdict:

input
2500 2500
000000000000000000000000000000...

correct output
3360

user output
(empty)

Test 49

Group: 49

Verdict: ACCEPTED

input
2500 2500
111111111111111111111111111111...

correct output
28

user output
28

Test 50

Group: 50

Verdict:

input
2500 2500
000000000000000000000000000000...

correct output
7348

user output
(empty)

Test 51

Group: 51

Verdict:

input
2500 2500
000000000000000000000000000000...

correct output
6622

user output
(empty)

Test 52

Group: 52

Verdict:

input
2500 2500
000000000000000000000000000000...

correct output
5593

user output
(empty)

Test 53

Group: 53

Verdict:

input
2500 2500
000000000000000000000000000000...

correct output
4545

user output
(empty)

Test 54

Group: 54

Verdict:

input
2500 2500
000000000000000000000000000000...

correct output
4067

user output
(empty)

Test 55

Group: 55

Verdict:

input
2500 2500
000000000000000000000000000000...

correct output
2806

user output
(empty)

Test 56

Group: 56

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
122500

user output
(empty)

Test 57

Group: 57

Verdict:

input
2500 2500
000000000000000000000000000000...

correct output
4674

user output
(empty)

Test 58

Group: 58

Verdict:

input
2500 2500
000000000000000000000000000000...

correct output
6272

user output
(empty)

Test 59

Group: 59

Verdict:

input
2500 2500
000000000000000000000000000000...

correct output
3337

user output
(empty)

Test 60

Group: 60

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
870

user output
(empty)

Test 61

Group: 61

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
532

user output
(empty)

Test 62

Group: 62

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
114271

user output
(empty)

Test 63

Group: 63

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
1560001

user output
(empty)

Test 64

Group: 64

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
62500

user output
(empty)

Test 65

Group: 65

Verdict:

input
2500 2500
000000000000000000000000000000...

correct output
1400

user output
(empty)

Test 66

Group: 66

Verdict: ACCEPTED

input
2500 2500
000000111111111111111111111111...

correct output
9910

user output
9910

Test 67

Group: 67

Verdict:

input
2500 2500
000000000000000000000000000000...

correct output
9879

user output
(empty)

Test 68

Group: 68

Verdict:

input
2500 2500
000000000000000000000000000000...

correct output
16224

user output
(empty)

Test 69

Group: 69

Verdict:

input
2500 2500
000000000000000000000000000000...

correct output
6300

user output
(empty)

Test 70

Group: 70

Verdict:

input
2000 2000
111111111111111111111111111111...

correct output
59760

user output
(empty)

Test 71

Group: 71

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
40480

user output
(empty)

Test 72

Group: 72

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
137159

user output
(empty)

Test 73

Group: 73

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
32110

user output
(empty)

Test 74

Group: 74

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
10914

user output
(empty)

Test 75

Group: 75

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
124074

user output
(empty)

Test 76

Group: 76

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
4617

user output
(empty)

Test 77

Group: 77

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
106981

user output
(empty)

Test 78

Group: 78

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
44980

user output
(empty)

Test 79

Group: 79

Verdict:

input
2500 2500
111111111111111111111111110000...

correct output
1365

user output
(empty)

Test 80

Group: 80

Verdict:

input
2500 2500
111111111111111111110000000000...

correct output
602

user output
(empty)

Test 81

Group: 81

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
2709

user output
(empty)

Test 82

Group: 82

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
149556

user output
(empty)

Test 83

Group: 83

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
11289

user output
(empty)

Test 84

Group: 84

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
366

user output
(empty)

Test 85

Group: 85

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
4814

user output
(empty)

Test 86

Group: 86

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
132

user output
(empty)

Test 87

Group: 87

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
589

user output
(empty)

Test 88

Group: 88

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
56448

user output
(empty)

Test 89

Group: 89

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
10044

user output
(empty)

Test 90

Group: 90

Verdict:

input
2000 2000
111111111111111111111111111111...

correct output
6384

user output
(empty)

Test 91

Group: 91

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
15330

user output
(empty)

Test 92

Group: 92

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
47759

user output
(empty)

Test 93

Group: 93

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
624

user output
(empty)

Test 94

Group: 94

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
16695

user output
(empty)

Test 95

Group: 95

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
19224

user output
(empty)

Test 96

Group: 96

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
89386

user output
(empty)

Test 97

Group: 97

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
243

user output
(empty)

Test 98

Group: 98

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
73840

user output
(empty)

Test 99

Group: 99

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
10764

user output
(empty)

Test 100

Group: 100

Verdict:

input
2500 2500
111111111111111111111111111111...

correct output
135

user output
(empty)