| | | 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.MagicSquaresInGrid; |
| | | 13 | | |
| | | 14 | | /// <inheritdoc /> |
| | | 15 | | public class MagicSquaresInGridBruteForce : IMagicSquaresInGrid |
| | | 16 | | { |
| | | 17 | | /// <summary> |
| | | 18 | | /// Time complexity - O(m * n) |
| | | 19 | | /// Space complexity - O(1) |
| | | 20 | | /// </summary> |
| | | 21 | | /// <param name="grid"></param> |
| | | 22 | | /// <returns></returns> |
| | | 23 | | public int NumMagicSquaresInside(int[][] grid) |
| | 7 | 24 | | { |
| | 7 | 25 | | var result = 0; |
| | | 26 | | |
| | 44 | 27 | | for (var i = 0; i < grid.Length - 2; i++) |
| | 15 | 28 | | { |
| | 180 | 29 | | for (var j = 0; j < grid[i].Length - 2; j++) |
| | 75 | 30 | | { |
| | 75 | 31 | | if (IsMagicSquare(grid, i, j)) |
| | 5 | 32 | | { |
| | 5 | 33 | | result++; |
| | 5 | 34 | | } |
| | 75 | 35 | | } |
| | 15 | 36 | | } |
| | | 37 | | |
| | 7 | 38 | | return result; |
| | 7 | 39 | | } |
| | | 40 | | |
| | | 41 | | private static bool IsMagicSquare(IReadOnlyList<int[]> grid, int i, int j) |
| | 75 | 42 | | { |
| | 75 | 43 | | if (grid[i + 1][j + 1] != 5 || grid[i + 1][j + 1] == grid[i][j + 1] || grid[i + 1][j + 1] == grid[i + 1][j]) |
| | 66 | 44 | | { |
| | 66 | 45 | | return false; |
| | | 46 | | } |
| | | 47 | | |
| | | 48 | | const int sum = 15; |
| | | 49 | | |
| | 50 | 50 | | for (var k = 0; k < 3; k++) |
| | 20 | 51 | | { |
| | 20 | 52 | | var rowSum = 0; |
| | 20 | 53 | | var columnSum = 0; |
| | | 54 | | |
| | 158 | 55 | | for (var l = 0; l < 3; l++) |
| | 60 | 56 | | { |
| | 60 | 57 | | if (grid[i + k][j + l] > 9) |
| | 1 | 58 | | { |
| | 1 | 59 | | return false; |
| | | 60 | | } |
| | | 61 | | |
| | 59 | 62 | | rowSum += grid[i + k][j + l]; |
| | 59 | 63 | | columnSum += grid[i + l][j + k]; |
| | 59 | 64 | | } |
| | | 65 | | |
| | 19 | 66 | | if (rowSum != sum || columnSum != sum) |
| | 3 | 67 | | { |
| | 3 | 68 | | return false; |
| | | 69 | | } |
| | 16 | 70 | | } |
| | | 71 | | |
| | 5 | 72 | | var leftDiagonalSum = 0; |
| | 5 | 73 | | var rightDiagonalSum = 0; |
| | | 74 | | |
| | 40 | 75 | | for (var k = 0; k < 3; k++) |
| | 15 | 76 | | { |
| | 15 | 77 | | leftDiagonalSum += grid[i + k][j + k]; |
| | 15 | 78 | | rightDiagonalSum += grid[i + k][2 + j - k]; |
| | 15 | 79 | | } |
| | | 80 | | |
| | 5 | 81 | | return leftDiagonalSum == sum && rightDiagonalSum == sum; |
| | 75 | 82 | | } |
| | | 83 | | } |