solves spiral matrix

Author: anishLearnsToCode

Diff for: README.md

@@ -52,6 +52,7 @@
 |  49  | [Group Anagrams](https://leetcode.com/problems/group-anagrams)                                                                                            |                                                                  [![Java](assets/java.png)](src/GroupAnagrams.java)                                                                  |                                                                                                                                   |
 |  50  | [Pow(x,n)](https://leetcode.com/problems/powx-n)                                                                                                          |                                                                      [![Java](assets/java.png)](src/Powxn.java)                                                                      |                                                                                                                                   |
 |  53  | [Maximum SubArray](https://leetcode.com/problems/maximum-subarray)                                                                                        |                                 [![Java](assets/java.png)](src/MaximumSubArray.java) [![Python](assets/python.png)](python/maximum_sum_subarray.py)                                  |                                                                                                                                   |
+|  54  | [Spiral Matrix](https://leetcode.com/problems/spiral-matrix)                                                                                              |                                                                  [![Java](assets/java.png)](src/SpiralMatrix.java)                                                                   |                                                                                                                                   |
 |  55  | [Jump Game](https://leetcode.com/problems/jump-game)                                                                                                      |                                                                    [![Java](assets/java.png)](src/JumpGame.java)                                                                     |                                                                                                                                   |
 |  58  | [Length of Last Word](https://leetcode.com/problems/length-of-last-word)                                                                                  |                                 [![Java](assets/java.png)](src/LengthOfLastWord.java) [![Python](assets/python.png)](python/length_of_last_word.py)                                  |                                                                                                                                   |
 |  66  | [Plus One](https://leetcode.com/problems/plus-one)                                                                                                        |                                           [![Java](assets/java.png)](src/PlusOne.java) [![Python](assets/python.png)](python/plus_one.py)                                            |                                                                                                                                   |

Diff for: src/SpiralMatrix.java

@@ -0,0 +1,32 @@
+import java.util.ArrayList;
+import java.util.List;
+
+public class SpiralMatrix {
+    public List<Integer> spiralOrder(int[][] matrix) {
+        final List<Integer> result = new ArrayList<>();
+        final int rows = matrix.length, columns = matrix[0].length, elements = rows * columns;
+        for (int i = 0, top = 0, bottom = rows, left = 0, right = columns ; ; ) {
+            for (int row = top, column = left ; column < right ; column++, i++) {
+                result.add(matrix[row][column]);
+            }
+            top++;
+            if (i == elements) break;
+            for (int row = top, column = right - 1 ; row < bottom ; row++, i++) {
+                result.add(matrix[row][column]);
+            }
+            right--;
+            if (i == elements) break;
+            for (int row = bottom - 1, column = right - 1 ; column >= left ; column--, i++) {
+                result.add(matrix[row][column]);
+            }
+            bottom--;
+            if (i == elements) break;
+            for (int row = bottom - 1, column = left ; row >= top ; row--, i++) {
+                result.add(matrix[row][column]);
+            }
+            left++;
+            if (i == elements) break;
+        }
+        return result;
+    }
+}