| | | 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.ShortestPalindrome; |
| | | 15 | | |
| | | 16 | | /// <inheritdoc /> |
| | | 17 | | public class ShortestPalindromeTwoPointers : IShortestPalindrome |
| | | 18 | | { |
| | | 19 | | /// <summary> |
| | | 20 | | /// Time complexity - O(n^2) |
| | | 21 | | /// Space complexity - O(n) |
| | | 22 | | /// </summary> |
| | | 23 | | /// <param name="s"></param> |
| | | 24 | | /// <returns></returns> |
| | | 25 | | public string ShortestPalindrome(string s) |
| | 12 | 26 | | { |
| | 12 | 27 | | if (s.Length <= 1) |
| | 4 | 28 | | { |
| | 4 | 29 | | return s; |
| | | 30 | | } |
| | | 31 | | |
| | 8 | 32 | | var left = 0; |
| | | 33 | | |
| | 136 | 34 | | for (var right = s.Length - 1; right >= 0; right--) |
| | 60 | 35 | | { |
| | 60 | 36 | | if (s[right] == s[left]) |
| | 51 | 37 | | { |
| | 51 | 38 | | left++; |
| | 51 | 39 | | } |
| | 60 | 40 | | } |
| | | 41 | | |
| | 8 | 42 | | if (left == s.Length) |
| | 4 | 43 | | { |
| | 4 | 44 | | return s; |
| | | 45 | | } |
| | | 46 | | |
| | 4 | 47 | | var resultStringBuilder = new StringBuilder(); |
| | | 48 | | |
| | 4 | 49 | | var nonPalindromeSuffix = s[left..]; |
| | | 50 | | |
| | 26 | 51 | | for (var i = nonPalindromeSuffix.Length - 1; i >= 0; i--) |
| | 9 | 52 | | { |
| | 9 | 53 | | resultStringBuilder.Append(nonPalindromeSuffix[i]); |
| | 9 | 54 | | } |
| | | 55 | | |
| | 4 | 56 | | resultStringBuilder.Append(ShortestPalindrome(s[..left])); |
| | 4 | 57 | | resultStringBuilder.Append(nonPalindromeSuffix); |
| | | 58 | | |
| | 4 | 59 | | return resultStringBuilder.ToString(); |
| | 12 | 60 | | } |
| | | 61 | | } |