| | | 1 | | // -------------------------------------------------------------------------------- |
| | | 2 | | // Copyright (C) 2026 Eugene Eremeev (also known as Yevhenii Yeriemeieiv). |
| | | 3 | | // All Rights Reserved. |
| | | 4 | | // -------------------------------------------------------------------------------- |
| | | 5 | | // This software is the confidential and proprietary information of Eugene Eremeev |
| | | 6 | | // (also known as Yevhenii Yeriemeieiv) ("Confidential Information"). You shall not |
| | | 7 | | // disclose such Confidential Information and shall use it only in accordance with |
| | | 8 | | // the terms of the license agreement you entered into with Eugene Eremeev (also |
| | | 9 | | // known as Yevhenii Yeriemeieiv). |
| | | 10 | | // -------------------------------------------------------------------------------- |
| | | 11 | | |
| | | 12 | | namespace LeetCode.Algorithms.SortVowelsInString; |
| | | 13 | | |
| | | 14 | | /// <inheritdoc /> |
| | | 15 | | public sealed class SortVowelsInStringCountingSort : ISortVowelsInString |
| | | 16 | | { |
| | | 17 | | private const string VowelOrder = "AEIOUaeiou"; |
| | | 18 | | |
| | | 19 | | /// <summary> |
| | | 20 | | /// Time complexity - O(n) |
| | | 21 | | /// Space complexity - O(1) |
| | | 22 | | /// </summary> |
| | | 23 | | /// <param name="s"></param> |
| | | 24 | | /// <returns></returns> |
| | | 25 | | public string SortVowels(string s) |
| | 2 | 26 | | { |
| | 2 | 27 | | Span<int> vowelFrequencies = stackalloc int[VowelOrder.Length]; |
| | | 28 | | |
| | 32 | 29 | | foreach (var c in s) |
| | 13 | 30 | | { |
| | 13 | 31 | | var vowelIndex = GetVowelIndex(c); |
| | | 32 | | |
| | 13 | 33 | | if (vowelIndex < 0) |
| | 9 | 34 | | { |
| | 9 | 35 | | continue; |
| | | 36 | | } |
| | | 37 | | |
| | 4 | 38 | | vowelFrequencies[vowelIndex]++; |
| | 4 | 39 | | } |
| | | 40 | | |
| | 2 | 41 | | var sCharArray = s.ToCharArray(); |
| | | 42 | | |
| | 2 | 43 | | var nextVowelIndex = 0; |
| | | 44 | | |
| | 30 | 45 | | for (var i = 0; i < sCharArray.Length; i++) |
| | 13 | 46 | | { |
| | 13 | 47 | | var vowelIndex = GetVowelIndex(sCharArray[i]); |
| | | 48 | | |
| | 13 | 49 | | if (vowelIndex < 0) |
| | 9 | 50 | | { |
| | 9 | 51 | | continue; |
| | | 52 | | } |
| | | 53 | | |
| | 10 | 54 | | while (nextVowelIndex < vowelFrequencies.Length && vowelFrequencies[nextVowelIndex] == 0) |
| | 6 | 55 | | { |
| | 6 | 56 | | nextVowelIndex++; |
| | 6 | 57 | | } |
| | | 58 | | |
| | 4 | 59 | | sCharArray[i] = VowelOrder[nextVowelIndex]; |
| | | 60 | | |
| | 4 | 61 | | vowelFrequencies[nextVowelIndex]--; |
| | 4 | 62 | | } |
| | | 63 | | |
| | 2 | 64 | | return new string(sCharArray); |
| | 2 | 65 | | } |
| | | 66 | | |
| | | 67 | | private static int GetVowelIndex(char c) |
| | 26 | 68 | | { |
| | 26 | 69 | | return c switch |
| | 26 | 70 | | { |
| | 0 | 71 | | 'A' => 0, |
| | 2 | 72 | | 'E' => 1, |
| | 0 | 73 | | 'I' => 2, |
| | 2 | 74 | | 'O' => 3, |
| | 0 | 75 | | 'U' => 4, |
| | 0 | 76 | | 'a' => 5, |
| | 4 | 77 | | 'e' => 6, |
| | 0 | 78 | | 'i' => 7, |
| | 0 | 79 | | 'o' => 8, |
| | 0 | 80 | | 'u' => 9, |
| | 18 | 81 | | _ => -1 |
| | 26 | 82 | | }; |
| | 26 | 83 | | } |
| | | 84 | | } |