| | | 1 | | // -------------------------------------------------------------------------------- |
| | | 2 | | // Copyright (C) 2025 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 | | using System.Text; |
| | | 13 | | |
| | | 14 | | namespace LeetCode.Algorithms.UniqueLength3PalindromicSubsequences; |
| | | 15 | | |
| | | 16 | | /// <inheritdoc /> |
| | | 17 | | public class UniqueLength3PalindromicSubsequencesBruteForce : IUniqueLength3PalindromicSubsequences |
| | | 18 | | { |
| | | 19 | | /// <summary> |
| | | 20 | | /// Time complexity - O(n^3) |
| | | 21 | | /// Space complexity - O(n) |
| | | 22 | | /// </summary> |
| | | 23 | | /// <param name="s"></param> |
| | | 24 | | /// <returns></returns> |
| | | 25 | | public int CountPalindromicSubsequence(string s) |
| | 3 | 26 | | { |
| | 3 | 27 | | var palindromesHashSet = new HashSet<string>(); |
| | | 28 | | |
| | 24 | 29 | | for (var i = 2; i < s.Length; i++) |
| | 9 | 30 | | { |
| | 62 | 31 | | for (var j = 0; j <= i - 2; j++) |
| | 22 | 32 | | { |
| | 22 | 33 | | if (s[j] != s[i]) |
| | 14 | 34 | | { |
| | 14 | 35 | | continue; |
| | | 36 | | } |
| | | 37 | | |
| | 50 | 38 | | for (var k = j + 1; k < i; k++) |
| | 17 | 39 | | { |
| | 17 | 40 | | var palindromeStringBuilder = new StringBuilder(); |
| | | 41 | | |
| | 17 | 42 | | palindromeStringBuilder.Append(s[i]); |
| | 17 | 43 | | palindromeStringBuilder.Append(s[k]); |
| | 17 | 44 | | palindromeStringBuilder.Append(s[j]); |
| | | 45 | | |
| | 17 | 46 | | var palindrome = palindromeStringBuilder.ToString(); |
| | | 47 | | |
| | 17 | 48 | | palindromesHashSet.Add(palindrome); |
| | 17 | 49 | | } |
| | 8 | 50 | | } |
| | 9 | 51 | | } |
| | | 52 | | |
| | 3 | 53 | | return palindromesHashSet.Count; |
| | 3 | 54 | | } |
| | | 55 | | } |