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  1. #include <bits/stdc++.h>
  2. #define int long long
  3. #define all(x) x.begin(), x.end()
  4. #define f1(i, n) for(int i=1;i<=n;++i)
  5. using namespace std;
  6.  
  7. const int maxn = 1e6 + 5;
  8. const int MOD = 1e9 + 7;
  9.  
  10. char A[30][30];
  11. int n, m;
  12.  
  13. bool check(int i, int j) {
  14. 	int cnt = 0;
  15. 	if (A[i - 1][j] == '#')
  16. 		++cnt;
  17. 	if (A[i][j - 1] == '#')
  18. 		++cnt;
  19. 	if (A[i][j + 1] == '#')
  20. 		++cnt;
  21. 	if (A[i + 1][j] == '#')
  22. 		++cnt;
  23. 	if (cnt != 2 and cnt != 4) return false;
  24. 	return true;
  25.  
  26. }
  27.  
  28. main() {
  29. 	ios::sync_with_stdio(false);
  30. 	cin.tie(nullptr);
  31. 	cout.tie(nullptr);
  32.  
  33. 	// . là trắng, # là đen
  34.  
  35. 	cin >> n >> m;
  36. 	f1(i, n) {
  37. 		string s;
  38. 		cin >> s;
  39. 		f1(j, m) {
  40. 			A[i][j] = s[j - 1];
  41. 		}
  42. 	}
  43.  
  44. 	// bool ok = false;
  45.  
  46. 	for (int i = 1; i <= n; ++i) {
  47. 		for (int j = 1; j <= m; ++j) {
  48. 			if (A[i][j] == '#') {
  49. 				if (!check(i, j)) {
  50. 					// cout<<"---"<<i<<" "<<j<<"---"<<endl;
  51. 					cout << "No";
  52. 					return 0;
  53. 				}
  54. 			}
  55. 		}
  56. 	}
  57. 	// if(!ok) cout<<"Yes";
  58. 	cout << "Yes";
  59.  
  60.  
  61.  
  62. }
  63.  
Success #stdin #stdout 0s 5308KB
comments (?)
stdin 
Standard input is empty
stdout 
Yes
https://ideone.com/qNfvkj
language:
C++14 (gcc 8.3)
created:
7 hours ago
visibility:
public

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