Alice and Bob are playing a game. Initially, Alice has a string word = "a"
.
You are given a positive integer k
.
Now Bob will ask Alice to perform the following operation forever:
- Generate a new string by changing each character in
word
to its next character in the English alphabet, and append it to the originalword
.
For example, performing the operation on "c"
generates "cd"
and performing the operation on "zb"
generates "zbac"
.
Return the value of the kth
character in word
, after enough operations have been done for word
to have at least k
characters.
Note that the character 'z'
can be changed to 'a'
in the operation.
Example 1:
Input: k = 5
Output: "b"
Explanation:
Initially, word = "a"
. We need to do the operation three times:
- Generated string is
"b"
,word
becomes"ab"
. - Generated string is
"bc"
,word
becomes"abbc"
. - Generated string is
"bccd"
,word
becomes"abbcbccd"
.
Example 2:
Input: k = 10
Output: "c"
Constraints:
1 <= k <= 500