| | | 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.FindMinimumTimeToReachLastRoom2; |
| | | 13 | | |
| | | 14 | | /// <inheritdoc /> |
| | | 15 | | public class FindMinimumTimeToReachLastRoom2PriorityQueue : IFindMinimumTimeToReachLastRoom2 |
| | | 16 | | { |
| | 1 | 17 | | private static readonly (int X, int Y)[] Directions = [(1, 0), (-1, 0), (0, 1), (0, -1)]; |
| | | 18 | | |
| | | 19 | | /// <summary> |
| | | 20 | | /// Time complexity - O(n * m * log(n * m)) |
| | | 21 | | /// Space complexity - O(n * m) |
| | | 22 | | /// </summary> |
| | | 23 | | /// <param name="moveTime"></param> |
| | | 24 | | /// <returns></returns> |
| | | 25 | | public int MinTimeToReach(int[][] moveTime) |
| | 3 | 26 | | { |
| | 3 | 27 | | var n = moveTime.Length; |
| | 3 | 28 | | var m = moveTime[0].Length; |
| | | 29 | | |
| | 3 | 30 | | var visited = new int[n, m]; |
| | | 31 | | |
| | 18 | 32 | | for (var i = 0; i < n; i++) |
| | 6 | 33 | | { |
| | 44 | 34 | | for (var j = 0; j < m; j++) |
| | 16 | 35 | | { |
| | 16 | 36 | | visited[i, j] = int.MaxValue; |
| | 16 | 37 | | } |
| | 6 | 38 | | } |
| | | 39 | | |
| | 3 | 40 | | visited[0, 0] = 0; |
| | | 41 | | |
| | 3 | 42 | | var priorityQueue = new PriorityQueue<(int X, int Y, int Step, int Time), int>(); |
| | | 43 | | |
| | 3 | 44 | | priorityQueue.Enqueue((0, 0, 0, 0), 0); |
| | | 45 | | |
| | 16 | 46 | | while (priorityQueue.Count > 0) |
| | 16 | 47 | | { |
| | 16 | 48 | | var item = priorityQueue.Dequeue(); |
| | | 49 | | |
| | 16 | 50 | | if (item.X == n - 1 && item.Y == m - 1) |
| | 3 | 51 | | { |
| | 3 | 52 | | return item.Time; |
| | | 53 | | } |
| | | 54 | | |
| | 143 | 55 | | foreach (var direction in Directions) |
| | 52 | 56 | | { |
| | 52 | 57 | | var targetX = item.X + direction.X; |
| | 52 | 58 | | var targetY = item.Y + direction.Y; |
| | | 59 | | |
| | 52 | 60 | | if (targetX < 0 || targetX >= n || targetY < 0 || targetY >= m) |
| | 22 | 61 | | { |
| | 22 | 62 | | continue; |
| | | 63 | | } |
| | | 64 | | |
| | 30 | 65 | | var targetTime = Math.Max(item.Time, moveTime[targetX][targetY]) + (item.Step % 2 == 0 ? 1 : 2); |
| | | 66 | | |
| | 30 | 67 | | if (targetTime >= visited[targetX, targetY]) |
| | 17 | 68 | | { |
| | 17 | 69 | | continue; |
| | | 70 | | } |
| | | 71 | | |
| | 13 | 72 | | visited[targetX, targetY] = targetTime; |
| | | 73 | | |
| | 13 | 74 | | priorityQueue.Enqueue((targetX, targetY, item.Step + 1, targetTime), targetTime); |
| | 13 | 75 | | } |
| | 13 | 76 | | } |
| | | 77 | | |
| | 0 | 78 | | return -1; |
| | 3 | 79 | | } |
| | | 80 | | } |