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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. int main() {
  5. 	int n;
  6. 	cin>>n;
  7. 	int dp[n+1][2][2];
  8. 	dp[1][0][0]=0;
  9. 	dp[1][0][1]=1;
  10. 	dp[1][1][0]=1;
  11. 	dp[1][1][1]=0;
  12. 	for(int len=2; len<=n; len++){
  13. 	dp[len][0][1]=dp[len-1][0][0]+dp[len-1][1][0];
  14. 	dp[len][0][0]=dp[len-1][1][0];
  15. 	dp[len][1][0]=dp[len-1][1][1]+dp[len-1][0][1];
  16. 	dp[len][1][1]=dp[len-1][0][1];
  17. }
  18. 	cout<<dp[n][0][0]+dp[n][0][1]+dp[n][1][0]+dp[n][1][1]<<endl;
  19. 	return 0;
  20. }
Success #stdin #stdout 0s 5308KB
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https://ideone.com/EyGsSW
language:
C++ (gcc 8.3)
created:
12 days ago
visibility:
public

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