Is Generate a String With Characters That Have Odd Counts easy or hard?

The problem is classified as Easy on LeetCode with a high acceptance rate around 78%. The main challenge is recognizing that only the parity of character counts matters, which leads to a simple greedy construction.

Generate a String With Characters That Have Odd Counts Python/Java solution

In Python or Java, check if n is odd. If it is, return 'a' repeated n times. If n is even, return 'a' repeated n-1 times followed by 'b'. Both implementations run in O(n) time and use constant auxiliary space.

What is the best approach for Generate a String With Characters That Have Odd Counts?

The optimal approach checks whether n is odd or even. If n is odd, return a string with the same character repeated n times. If n is even, return n-1 copies of one character and one copy of another character. This guarantees both counts are odd and runs in O(n) time with O(1) extra space.

Is Generate a String With Characters That Have Odd Counts asked at Google/Amazon/Meta?

This problem is categorized as an easy string construction question and appears in coding practice sets used by companies like Amazon and Google for warm-up or screening rounds. It tests logical reasoning about parity rather than complex algorithms.

What data structure is used in Generate a String With Characters That Have Odd Counts?

The solution primarily uses basic string construction. No advanced data structures such as hash maps or arrays are required because the parity trick allows a direct construction with one or two characters.

What is the time complexity of Generate a String With Characters That Have Odd Counts?

The time complexity is O(n) because the algorithm constructs a string of length n. Each character is appended once during the build process. The space complexity is O(1) beyond the output string since only a few variables are used.

1374. Generate a String With Characters That Have Odd Counts - Practice Online

Q: How to solve Generate a String With Characters That Have Odd Counts in O(n)?

Check the parity of n. If n is odd, generate a string like "aaaa..." with n repetitions of the same character. If n is even, generate n-1 copies of 'a' and append 'b'. Both character frequencies become odd, and the construction takes linear time.

Given an integer n, return 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