Spiral Matrix

Author: anantkaushik

054-spiral-matrix.py

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+"""
+Problem Link: https://leetcode.com/problems/spiral-matrix/
+
+Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.
+
+Example 1:
+Input:
+[
+ [ 1, 2, 3 ],
+ [ 4, 5, 6 ],
+ [ 7, 8, 9 ]
+]
+Output: [1,2,3,6,9,8,7,4,5]
+
+Example 2:
+Input:
+[
+  [1, 2, 3, 4],
+  [5, 6, 7, 8],
+  [9,10,11,12]
+]
+Output: [1,2,3,4,8,12,11,10,9,5,6,7]
+"""
+class Solution(object):
+    def spiralOrder(self, matrix):
+        """
+        :type matrix: List[List[int]]
+        :rtype: List[int]
+        """
+        if matrix == []:
+            return []
+        top = left = 0
+        bottom = len(matrix) - 1
+        right = len(matrix[0]) - 1
+        direction = 0
+        res = []
+        while top <= bottom and left <= right:
+            if direction == 0:
+                for i in range(left,right+1):
+                    res.append(matrix[top][i])
+                top += 1
+            elif direction == 1:
+                for i in range(top,bottom+1):
+                    res.append(matrix[i][right])
+                right -= 1
+            elif direction == 2:
+                for i in range(right,left-1,-1):
+                    res.append(matrix[bottom][i])
+                bottom -= 1
+            elif direction == 3:
+                for i in range(bottom, top-1, -1):
+                    res.append(matrix[i][left])
+                left += 1
+            direction = (direction+1) % 4
+        return res