| | | 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.OpenTheLock; |
| | | 13 | | |
| | | 14 | | /// <inheritdoc /> |
| | | 15 | | public class OpenTheLockBreadthFirstSearch : IOpenTheLock |
| | | 16 | | { |
| | | 17 | | private const string Start = "0000"; |
| | | 18 | | |
| | | 19 | | /// <summary> |
| | | 20 | | /// Time complexity - O(n * m) |
| | | 21 | | /// Space complexity - O(n) |
| | | 22 | | /// </summary> |
| | | 23 | | /// <param name="deadends"></param> |
| | | 24 | | /// <param name="target"></param> |
| | | 25 | | /// <returns></returns> |
| | | 26 | | public int OpenLock(string[] deadends, string target) |
| | 4 | 27 | | { |
| | 4 | 28 | | var deadendsHashSet = new HashSet<string>(deadends); |
| | 4 | 29 | | var visitedHashSet = new HashSet<string> { Start }; |
| | 4 | 30 | | var queue = new Queue<(string, int)>(); |
| | | 31 | | |
| | 4 | 32 | | queue.Enqueue((Start, 0)); |
| | | 33 | | |
| | 4 | 34 | | if (deadendsHashSet.Contains(Start)) |
| | 1 | 35 | | { |
| | 1 | 36 | | return -1; |
| | | 37 | | } |
| | | 38 | | |
| | 10865 | 39 | | while (queue.Count > 0) |
| | 10864 | 40 | | { |
| | 10864 | 41 | | var (state, steps) = queue.Dequeue(); |
| | | 42 | | |
| | 10864 | 43 | | if (state == target) |
| | 2 | 44 | | { |
| | 2 | 45 | | return steps; |
| | | 46 | | } |
| | | 47 | | |
| | 108620 | 48 | | for (var i = 0; i < state.Length; i++) |
| | 43448 | 49 | | { |
| | 43448 | 50 | | var digit = char.GetNumericValue(state[i]); |
| | | 51 | | |
| | 304136 | 52 | | foreach (var move in new[] { -1, 1 }) |
| | 86896 | 53 | | { |
| | 86896 | 54 | | var newDigit = (digit + move + 10) % 10; |
| | 86896 | 55 | | var newState = state[..i] + newDigit + state[(i + 1)..]; |
| | | 56 | | |
| | 86896 | 57 | | if (visitedHashSet.Contains(newState) || deadendsHashSet.Contains(newState)) |
| | 75307 | 58 | | { |
| | 75307 | 59 | | continue; |
| | | 60 | | } |
| | | 61 | | |
| | 11589 | 62 | | visitedHashSet.Add(newState); |
| | 11589 | 63 | | queue.Enqueue((newState, steps + 1)); |
| | 11589 | 64 | | } |
| | 43448 | 65 | | } |
| | 10862 | 66 | | } |
| | | 67 | | |
| | 1 | 68 | | return -1; |
| | 4 | 69 | | } |
| | | 70 | | } |