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  1. #include<iostream>
  2. using namespace std;
  3. long long dp[26][26];
  4. int main()
  5. {
  6. 	dp[0][0]=1;
  7. 	for(int i=1;i<=25;i++)
  8. 	{
  9. 		dp[i][0]=dp[i-1][1];
  10. 		for(int j=i%2;j<=i;j+=2)
  11. 		{
  12. 			dp[i][j]=dp[i-1][j-1]+dp[i-1][j+1];
  13. 		}
  14. 	}
  15.  
  16. 	int n;
  17. 	while(cin>>n)
  18. 	{
  19. 		long long ans=0;
  20. 		for(int i=n%2;i<=n;i+=2)
  21. 			ans+=dp[n][i]*dp[n][i];
  22. 		cout<<ans<<endl;
  23. 	}
  24. }
  25.  
Success #stdin #stdout 0s 3348KB
comments (?)
stdin 
3
4
25
stdout 
5
14
4861946401452
https://ideone.com/MfI3rx
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
secret

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