Is Reverse Words With Same Vowel Count easy or hard?

Reverse Words With Same Vowel Count is typically categorized as a Medium problem. The difficulty comes from recognizing that words must be grouped by vowel count before performing the reversal. Once the grouping step is clear, the remaining logic is straightforward simulation with two pointers.

Reverse Words With Same Vowel Count Python/Java solution

The implementation is nearly identical across languages. Split the string into words, compute vowel counts with a helper function, group indices in a hash map, and reverse each group using two pointers. Python uses dictionaries and lists, while Java uses HashMap > with array or list swaps.

How to solve Reverse Words With Same Vowel Count in O(n)?

Split the sentence into words, compute the vowel count for each word, and store its index in a map keyed by that count. For each group of indices, use two pointers to swap the words at the start and end of the group until the pointers meet. Because every word is processed a constant number of times, the algorithm remains linear.

What is the best approach for Reverse Words With Same Vowel Count?

The best approach groups words by their vowel count and then reverses the words within each group using a two‑pointer technique. First split the sentence, compute vowel counts, and store indices in a hash map keyed by the count. Reverse each index group in place. This runs in O(n) time with O(n) extra space.

Is Reverse Words With Same Vowel Count asked at Google/Amazon/Meta?

Problems involving grouping words by properties and performing in-place reversals frequently appear in coding interviews at large tech companies. Variants that combine string processing, hash maps, and two-pointer techniques are common in Google, Amazon, and Meta interview question sets.

What data structure is used in Reverse Words With Same Vowel Count?

The typical implementation uses an array or list for the words and a hash map that groups word indices by vowel count. Two pointers are then applied within each group to reverse the order. This combination keeps the solution simple and efficient.

What is the time complexity of Reverse Words With Same Vowel Count?

The optimal solution runs in O(n) time where n is the total number of characters or words in the sentence. Each word is scanned once to count vowels and each group is reversed with linear swaps. Auxiliary storage for grouped indices leads to O(n) space complexity.

Description Hints 1 Solution Video 0:18

3775. Reverse Words With Same Vowel Count

Medium66.6% acceptance

You are given a string s consisting of lowercase English words, each separated by a single space.

Determine how many vowels appear in the first word. Then, reverse each following word that has the same vowel count. Leave all remaining words unchanged.

Return the resulting string.

Vowels are 'a', 'e', 'i', 'o', and 'u'.

Example 1:

Input: s = "cat and mice"

Output: "cat dna mice"

Explanation:

The first word "cat" has 1 vowel.
"and" has 1 vowel, so it is reversed to form "dna".
"mice" has 2 vowels, so it remains unchanged.
Thus, the resulting string is "cat dna mice".

Example 2:

Input: s = "book is nice"

Output: "book is ecin"

Explanation:

The first word "book" has 2 vowels.
"is" has 1 vowel, so it remains unchanged.
"nice" has 2 vowels, so it is reversed to form "ecin".
Thus, the resulting string is "book is ecin".

Example 3:

Input: s = "banana healthy"

Output: "banana healthy"

Explanation:

The first word "banana" has 3 vowels.
"healthy" has 2 vowels, so it remains unchanged.
Thus, the resulting string is "banana healthy".

Constraints:

1 <= s.length <= 10⁵
s consists of lowercase English letters and spaces.
Words in s are separated by a single space.
s does not contain leading or trailing spaces.

Topics

Hints open one at a time

Hint 1

Simulate as described

0:18

Still stuck?Read the written solution, or watch a walkthrough.

Open solution

LanguageLoading editor…

1class Solution:
2    def reverseWords(self, s: str) -> str:
3        

Starter codePython 3Spaces: 4

Examples

Case 1Case 2Case 3

Input

"cat and mice"

Input

"book is nice"

Input

"banana healthy"

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