LeetCode 1374. Generate a String With Characters That Have Odd Counts

Description

https://leetcode.com/problems/generate-a-string-with-characters-that-have-odd-counts/

Given an integer nreturn a string with n characters such that each character in such string occurs an odd number of times.

The returned string must contain only lowercase English letters. If there are multiples valid strings, return any of them.  

Example 1:

Input: n = 4
Output: "pppz"
Explanation: "pppz" is a valid string since the character 'p' occurs three times and the character 'z' occurs once. Note that there are many other valid strings such as "ohhh" and "love".

Example 2:

Input: n = 2
Output: "xy"
Explanation: "xy" is a valid string since the characters 'x' and 'y' occur once. Note that there are many other valid strings such as "ag" and "ur".

Example 3:

Input: n = 7
Output: "holasss"

Constraints:

  • 1 <= n <= 500

Explanation

For even length, we can return (n – 1) times one letter and one different letter. For odd length, we can return n times a same letter.

Python Solution

class Solution:
    def generateTheString(self, n: int) -> str:
        if n < 2:
            return 'a'
        
        if n % 2 == 0:
            
            return 'a' * (n - 1) + 'b' * 1
        else:
            return 'a' * n
        
        return ""
            
  • Time Complexity: O(N).
  • Space Complexity: O(N).

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