| | | 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 | | namespace LeetCode.Algorithms.CountPrefixAndSuffixPairs1; |
| | | 13 | | |
| | | 14 | | /// <inheritdoc /> |
| | | 15 | | public class CountPrefixAndSuffixPairs1Trie : ICountPrefixAndSuffixPairs1 |
| | | 16 | | { |
| | 3 | 17 | | private readonly Node _prefixRoot = new(); |
| | 3 | 18 | | private readonly Node _suffixRoot = new(); |
| | | 19 | | |
| | | 20 | | /// <summary> |
| | | 21 | | /// Time complexity - O(n^2 * L), where L is the average word length |
| | | 22 | | /// Space complexity - O(n * L), where L is the average word length |
| | | 23 | | /// </summary> |
| | | 24 | | /// <param name="words"></param> |
| | | 25 | | /// <returns></returns> |
| | | 26 | | public int CountPrefixSuffixPairs(string[] words) |
| | 3 | 27 | | { |
| | 29 | 28 | | foreach (var word in words) |
| | 10 | 29 | | { |
| | 10 | 30 | | InsertPrefix(word); |
| | 10 | 31 | | InsertSuffix(word); |
| | 10 | 32 | | } |
| | | 33 | | |
| | 3 | 34 | | var count = 0; |
| | | 35 | | |
| | 26 | 36 | | for (var i = 0; i < words.Length; i++) |
| | 10 | 37 | | { |
| | 46 | 38 | | for (var j = i + 1; j < words.Length; j++) |
| | 13 | 39 | | { |
| | 13 | 40 | | if (IsPrefixAndSuffix(words[i], words[j])) |
| | 6 | 41 | | { |
| | 6 | 42 | | count++; |
| | 6 | 43 | | } |
| | 13 | 44 | | } |
| | 10 | 45 | | } |
| | | 46 | | |
| | 3 | 47 | | return count; |
| | 3 | 48 | | } |
| | | 49 | | |
| | | 50 | | private bool IsPrefixAndSuffix(string prefixSuffix, string word) |
| | 13 | 51 | | { |
| | 13 | 52 | | return IsPrefix(prefixSuffix, word) && IsSuffix(prefixSuffix, word); |
| | 13 | 53 | | } |
| | | 54 | | |
| | | 55 | | private bool IsPrefix(string prefix, string word) |
| | 13 | 56 | | { |
| | 13 | 57 | | var currentNode = _prefixRoot; |
| | | 58 | | |
| | 54 | 59 | | return word.All(c => currentNode.Nodes.TryGetValue(c, out currentNode)) && word.StartsWith(prefix); |
| | 13 | 60 | | } |
| | | 61 | | |
| | | 62 | | private bool IsSuffix(string suffix, string word) |
| | 6 | 63 | | { |
| | 6 | 64 | | var currentNode = _suffixRoot; |
| | 58 | 65 | | for (var i = word.Length - 1; i >= 0; i--) |
| | 23 | 66 | | { |
| | 23 | 67 | | if (!currentNode.Nodes.TryGetValue(word[i], out currentNode)) |
| | 0 | 68 | | { |
| | 0 | 69 | | return false; |
| | | 70 | | } |
| | 23 | 71 | | } |
| | | 72 | | |
| | 6 | 73 | | return word.EndsWith(suffix); |
| | 6 | 74 | | } |
| | | 75 | | |
| | | 76 | | private void InsertPrefix(string word) |
| | 10 | 77 | | { |
| | 10 | 78 | | var currentNode = _prefixRoot; |
| | | 79 | | |
| | 88 | 80 | | foreach (var c in word) |
| | 29 | 81 | | { |
| | 29 | 82 | | if (currentNode.Nodes.TryGetValue(c, out var node)) |
| | 11 | 83 | | { |
| | 11 | 84 | | currentNode = node; |
| | 11 | 85 | | } |
| | | 86 | | else |
| | 18 | 87 | | { |
| | 18 | 88 | | currentNode.Nodes[c] = new Node(); |
| | | 89 | | |
| | 18 | 90 | | currentNode = currentNode.Nodes[c]; |
| | 18 | 91 | | } |
| | 29 | 92 | | } |
| | 10 | 93 | | } |
| | | 94 | | |
| | | 95 | | private void InsertSuffix(string word) |
| | 10 | 96 | | { |
| | 10 | 97 | | var currentNode = _suffixRoot; |
| | | 98 | | |
| | 78 | 99 | | for (var i = word.Length - 1; i >= 0; i--) |
| | 29 | 100 | | { |
| | 29 | 101 | | if (currentNode.Nodes.TryGetValue(word[i], out var node)) |
| | 12 | 102 | | { |
| | 12 | 103 | | currentNode = node; |
| | 12 | 104 | | } |
| | | 105 | | else |
| | 17 | 106 | | { |
| | 17 | 107 | | currentNode.Nodes[word[i]] = new Node(); |
| | | 108 | | |
| | 17 | 109 | | currentNode = currentNode.Nodes[word[i]]; |
| | 17 | 110 | | } |
| | 29 | 111 | | } |
| | 10 | 112 | | } |
| | | 113 | | |
| | | 114 | | private class Node |
| | | 115 | | { |
| | 233 | 116 | | public Dictionary<char, Node> Nodes { get; } = new(); |
| | | 117 | | } |
| | | 118 | | } |