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| 1 | +// Source : https://leetcode.com/problems/rotating-the-box/ |
| 2 | +// Author : Hao Chen |
| 3 | +// Date : 2021-05-22 |
| 4 | + |
| 5 | +/***************************************************************************************************** |
| 6 | + * |
| 7 | + * You are given an m x n matrix of characters box representing a side-view of a box. Each cell of the |
| 8 | + * box is one of the following: |
| 9 | + * |
| 10 | + * A stone '#' |
| 11 | + * A stationary obstacle '*' |
| 12 | + * Empty '.' |
| 13 | + * |
| 14 | + * The box is rotated 90 degrees clockwise, causing some of the stones to fall due to gravity. Each |
| 15 | + * stone falls down until it lands on an obstacle, another stone, or the bottom of the box. Gravity |
| 16 | + * does not affect the obstacles' positions, and the inertia from the box's rotation does not affect |
| 17 | + * the stones' horizontal positions. |
| 18 | + * |
| 19 | + * It is guaranteed that each stone in box rests on an obstacle, another stone, or the bottom of the |
| 20 | + * box. |
| 21 | + * |
| 22 | + * Return an n x m matrix representing the box after the rotation described above. |
| 23 | + * |
| 24 | + * Example 1: |
| 25 | + * |
| 26 | + * Input: box = [["#",".","#"]] |
| 27 | + * Output: [["."], |
| 28 | + * ["#"], |
| 29 | + * ["#"]] |
| 30 | + * |
| 31 | + * Example 2: |
| 32 | + * |
| 33 | + * Input: box = [["#",".","*","."], |
| 34 | + * ["#","#","*","."]] |
| 35 | + * Output: [["#","."], |
| 36 | + * ["#","#"], |
| 37 | + * ["*","*"], |
| 38 | + * [".","."]] |
| 39 | + * |
| 40 | + * Example 3: |
| 41 | + * |
| 42 | + * Input: box = [["#","#","*",".","*","."], |
| 43 | + * ["#","#","#","*",".","."], |
| 44 | + * ["#","#","#",".","#","."]] |
| 45 | + * Output: [[".","#","#"], |
| 46 | + * [".","#","#"], |
| 47 | + * ["#","#","*"], |
| 48 | + * ["#","*","."], |
| 49 | + * ["#",".","*"], |
| 50 | + * ["#",".","."]] |
| 51 | + * |
| 52 | + * Constraints: |
| 53 | + * |
| 54 | + * m == box.length |
| 55 | + * n == box[i].length |
| 56 | + * 1 <= m, n <= 500 |
| 57 | + * box[i][j] is either '#', '*', or '.'. |
| 58 | + ******************************************************************************************************/ |
| 59 | + |
| 60 | +classSolution { |
| 61 | +public: |
| 62 | +voidrotate(vector<vector<char>>& src, vector<vector<char>>& dest) { |
| 63 | +int m = src.size(); |
| 64 | +for(int row=0; row<dest.size(); row++) { |
| 65 | +for(int col=0; col<dest[row].size(); col++) { |
| 66 | + dest[row][col] = src[m-col-1][row]; |
| 67 | + } |
| 68 | + } |
| 69 | + } |
| 70 | +voidgravity(vector<vector<char>>& box) { |
| 71 | +int m = box.size(); |
| 72 | +int n = box[0].size(); |
| 73 | +for(int col=0; col<n; col++) { |
| 74 | +int bottom = m -1; |
| 75 | +for(int row=m-1; row>=0; row-- ) { |
| 76 | + |
| 77 | +if (box[row][col] =='#') { |
| 78 | + box[row][col] ='.'; |
| 79 | + box[bottom][col] ='#'; |
| 80 | + bottom--; |
| 81 | + }elseif (box[row][col] =='*') { |
| 82 | + bottom = row-1; |
| 83 | + } |
| 84 | + } |
| 85 | + } |
| 86 | + } |
| 87 | + vector<vector<char>>rotateTheBox(vector<vector<char>>& box) { |
| 88 | +int row = box.size(); |
| 89 | +int col = box[0].size(); |
| 90 | + vector<vector<char>>result(col, vector<char>(row,'.')); |
| 91 | +rotate(box, result); |
| 92 | +gravity(result); |
| 93 | +return result; |
| 94 | + } |
| 95 | +}; |