| | | 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.SmallestPairWithDifferentFrequencies; |
| | | 13 | | |
| | | 14 | | /// <inheritdoc /> |
| | | 15 | | public sealed class SmallestPairWithDifferentFrequenciesLookup : ISmallestPairWithDifferentFrequencies |
| | | 16 | | { |
| | 1 | 17 | | private static readonly int[] EmptyPair = [-1, -1]; |
| | | 18 | | |
| | | 19 | | /// <summary> |
| | | 20 | | /// Time complexity - O(n) |
| | | 21 | | /// Space complexity - O(1) |
| | | 22 | | /// </summary> |
| | | 23 | | /// <param name="nums"></param> |
| | | 24 | | /// <returns></returns> |
| | | 25 | | public int[] MinDistinctFreqPair(int[] nums) |
| | 3 | 26 | | { |
| | 3 | 27 | | if (nums.Length < 3) |
| | 2 | 28 | | { |
| | 2 | 29 | | return EmptyPair; |
| | | 30 | | } |
| | | 31 | | |
| | 1 | 32 | | Span<int> frequencies = stackalloc int[101]; |
| | | 33 | | |
| | 14 | 34 | | for (var i = 0; i < nums.Length; i++) |
| | 6 | 35 | | { |
| | 6 | 36 | | var num = nums[i]; |
| | | 37 | | |
| | 6 | 38 | | frequencies[num]++; |
| | 6 | 39 | | } |
| | | 40 | | |
| | 1 | 41 | | var xFrequency = 0; |
| | 1 | 42 | | var x = -1; |
| | 1 | 43 | | var y = -1; |
| | | 44 | | |
| | 10 | 45 | | for (var i = 0; i < frequencies.Length; i++) |
| | 5 | 46 | | { |
| | 5 | 47 | | var frequency = frequencies[i]; |
| | | 48 | | |
| | 5 | 49 | | if (frequency <= 0) |
| | 1 | 50 | | { |
| | 1 | 51 | | continue; |
| | | 52 | | } |
| | | 53 | | |
| | 4 | 54 | | if (x < 0) |
| | 1 | 55 | | { |
| | 1 | 56 | | x = i; |
| | 1 | 57 | | xFrequency = frequency; |
| | 1 | 58 | | } |
| | 3 | 59 | | else if (y < 0) |
| | 2 | 60 | | { |
| | 2 | 61 | | if (frequency != xFrequency) |
| | 1 | 62 | | { |
| | 1 | 63 | | y = i; |
| | 1 | 64 | | } |
| | 2 | 65 | | } |
| | | 66 | | else |
| | 1 | 67 | | { |
| | 1 | 68 | | break; |
| | | 69 | | } |
| | 3 | 70 | | } |
| | | 71 | | |
| | 1 | 72 | | return y == -1 ? EmptyPair : [x, y]; |
| | 3 | 73 | | } |
| | | 74 | | } |