| | | 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.NumberOfEquivalentDominoPairs; |
| | | 13 | | |
| | | 14 | | /// <inheritdoc /> |
| | | 15 | | public class NumberOfEquivalentDominoPairsFrequencyDictionary : INumberOfEquivalentDominoPairs |
| | | 16 | | { |
| | | 17 | | /// <summary> |
| | | 18 | | /// Time complexity - O(n) |
| | | 19 | | /// Space complexity - O(n) |
| | | 20 | | /// </summary> |
| | | 21 | | /// <param name="dominoes"></param> |
| | | 22 | | /// <returns></returns> |
| | | 23 | | public int NumEquivDominoPairs(int[][] dominoes) |
| | 3 | 24 | | { |
| | 3 | 25 | | var result = 0; |
| | | 26 | | |
| | 3 | 27 | | var frequencyDictionary = new Dictionary<(int, int), int>(); |
| | | 28 | | |
| | 39 | 29 | | foreach (var domino in dominoes) |
| | 15 | 30 | | { |
| | 15 | 31 | | var a = Math.Min(domino[0], domino[1]); |
| | 15 | 32 | | var b = Math.Max(domino[0], domino[1]); |
| | 15 | 33 | | var key = (a, b); |
| | | 34 | | |
| | 15 | 35 | | if (frequencyDictionary.TryGetValue(key, out var frequency)) |
| | 6 | 36 | | { |
| | 6 | 37 | | result += frequency; |
| | | 38 | | |
| | 6 | 39 | | frequencyDictionary[key] = frequency + 1; |
| | 6 | 40 | | } |
| | | 41 | | else |
| | 9 | 42 | | { |
| | 9 | 43 | | frequencyDictionary[key] = 1; |
| | 9 | 44 | | } |
| | 15 | 45 | | } |
| | | 46 | | |
| | 3 | 47 | | return result; |
| | 3 | 48 | | } |
| | | 49 | | } |