题目描述
You are given an integer, $N$. Your task is to print an alphabet rangoli of size $N$.
(Rangoli is a form of Indian folk art based on creation of patterns.)
Different sizes of alphabet rangoli are shown below:
size 3
----c----
--c-b-c--
c-b-a-b-c
--c-b-c--
----c----
size 5
--------e--------
------e-d-e------
----e-d-c-d-e----
--e-d-c-b-c-d-e--
e-d-c-b-a-b-c-d-e
--e-d-c-b-c-d-e--
----e-d-c-d-e----
------e-d-e------
--------e--------
size 10
------------------j------------------
----------------j-i-j----------------
--------------j-i-h-i-j--------------
------------j-i-h-g-h-i-j------------
----------j-i-h-g-f-g-h-i-j----------
--------j-i-h-g-f-e-f-g-h-i-j--------
------j-i-h-g-f-e-d-e-f-g-h-i-j------
----j-i-h-g-f-e-d-c-d-e-f-g-h-i-j----
--j-i-h-g-f-e-d-c-b-c-d-e-f-g-h-i-j--
j-i-h-g-f-e-d-c-b-a-b-c-d-e-f-g-h-i-j
--j-i-h-g-f-e-d-c-b-c-d-e-f-g-h-i-j--
----j-i-h-g-f-e-d-c-d-e-f-g-h-i-j----
------j-i-h-g-f-e-d-e-f-g-h-i-j------
--------j-i-h-g-f-e-f-g-h-i-j--------
----------j-i-h-g-f-g-h-i-j----------
------------j-i-h-g-h-i-j------------
--------------j-i-h-i-j--------------
----------------j-i-j----------------
------------------j------------------
The center of the rangoli has the first alphabet letter a, and the boundary has the $N^{th}$ alphabet letter (in alphabetical order).
Function Description
Complete the rangoli function in the editor below.
rangoli has the following parameters:
int size: the size of the rangoli
Returns
string: a single string made up of each of the lines of the rangoli separated by $a newline character (\n)$
Input Format
Only one line of input containing $size$, the size of the rangoli.
Constraints
$0<size<27$
Sample Input
5
Sample Output
--------e--------
------e-d-e------
----e-d-c-d-e----
--e-d-c-b-c-d-e--
e-d-c-b-a-b-c-d-e
--e-d-c-b-c-d-e--
----e-d-c-d-e----
------e-d-e------
--------e--------
输入格式
见题面
输出格式
见题面