| | | 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.ClosestPrimeNumbersInRange; |
| | | 13 | | |
| | | 14 | | /// <inheritdoc /> |
| | | 15 | | public class ClosestPrimeNumbersInRangeBruteForce : IClosestPrimeNumbersInRange |
| | | 16 | | { |
| | | 17 | | /// <summary> |
| | | 18 | | /// Time complexity - O((R−L) * sqrt(R)) |
| | | 19 | | /// Space complexity - O(1) |
| | | 20 | | /// </summary> |
| | | 21 | | /// <param name="left"></param> |
| | | 22 | | /// <param name="right"></param> |
| | | 23 | | /// <returns></returns> |
| | | 24 | | public int[] ClosestPrimes(int left, int right) |
| | 2 | 25 | | { |
| | 2 | 26 | | var minNum1 = 0; |
| | 2 | 27 | | var minNum2 = int.MaxValue; |
| | 2 | 28 | | var num1 = -1; |
| | 2 | 29 | | var num2 = -1; |
| | | 30 | | |
| | 16 | 31 | | for (var num = left; num <= right; num++) |
| | 7 | 32 | | { |
| | 7 | 33 | | if (!IsPrime(num)) |
| | 4 | 34 | | { |
| | 4 | 35 | | continue; |
| | | 36 | | } |
| | | 37 | | |
| | 3 | 38 | | num1 = num2; |
| | 3 | 39 | | num2 = num; |
| | | 40 | | |
| | 3 | 41 | | if (minNum2 - minNum1 > num2 - num1) |
| | 3 | 42 | | { |
| | 3 | 43 | | minNum1 = num1; |
| | 3 | 44 | | minNum2 = num2; |
| | 3 | 45 | | } |
| | | 46 | | |
| | 3 | 47 | | if (minNum2 - minNum1 == 2) |
| | 1 | 48 | | { |
| | 1 | 49 | | break; |
| | | 50 | | } |
| | 2 | 51 | | } |
| | | 52 | | |
| | 2 | 53 | | if (num1 <= 0 || num2 <= 0) |
| | 1 | 54 | | { |
| | 1 | 55 | | return [-1, -1]; |
| | | 56 | | } |
| | | 57 | | |
| | 1 | 58 | | return [minNum1, minNum2]; |
| | 2 | 59 | | } |
| | | 60 | | |
| | | 61 | | private static bool IsPrime(int num) |
| | 7 | 62 | | { |
| | 7 | 63 | | switch (num) |
| | | 64 | | { |
| | | 65 | | case <= 1: |
| | 0 | 66 | | return false; |
| | | 67 | | case 2 or 3: |
| | 0 | 68 | | return true; |
| | | 69 | | } |
| | | 70 | | |
| | 7 | 71 | | if (num % 2 == 0) |
| | 4 | 72 | | { |
| | 4 | 73 | | return false; |
| | | 74 | | } |
| | | 75 | | |
| | 10 | 76 | | for (var i = 3; i * i <= num; i += 2) |
| | 2 | 77 | | { |
| | 2 | 78 | | if (num % i == 0) |
| | 0 | 79 | | { |
| | 0 | 80 | | return false; |
| | | 81 | | } |
| | 2 | 82 | | } |
| | | 83 | | |
| | 3 | 84 | | return true; |
| | 7 | 85 | | } |
| | | 86 | | } |