Fibonacci strings generation#8295

Fibonacci strings generation

ثانية

128 ميغابايت

متوسط

Generate the $n$ -th Fibonacci string, which is defined by the following recurrence relation:

$f (0) = " a "$ f(0) = "a";
$f (1) = " b "$ f(1) = "b";
$f (n) = f (n - 1) + f (n - 2)$ f(n) = f(n - 1) + f(n - 2), where the " $+$ " denotes string concatenation.

For example:

f (3) = f (2) + f (1) = (f (1) + f (0)) + f (1) = " b " + " a " + " b " = " bab "

f(3) = f(2) + f(1) = (f(1) + f(0)) + f(1) = "b" + "a" + "b" = "bab"

المدخلات

One integer $n (0 \leq n \leq 20)$ n~(0 \le n \le 20).

Print the $n$ -th Fibonacci string.

مثال 1

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مثال 2

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f (0) = " a "

f (1) = " b "

f (n) = f (n - 1) + f (n - 2)

f (3) = f (2) + f (1) = (f (1) + f (0)) + f (1) = " b " + " a " + " b " = " bab "

n (0 \leq n \leq 20)