Create Spiral Matrix - Leetcode 54.py

Author: gahogg

Spiral Matrix - Leetcode 54.py

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+class Solution:
+    def spiralOrder(self, matrix: List[List[int]]) -> List[int]:
+        m, n = len(matrix), len(matrix[0])
+        ans = []
+        i, j = 0, 0
+        UP, RIGHT, DOWN, LEFT = 0, 1, 2, 3
+        direction = RIGHT
+
+        UP_WALL = 0
+        RIGHT_WALL = n
+        DOWN_WALL = m
+        LEFT_WALL = -1
+
+        while len(ans) != m*n:
+            if direction == RIGHT:
+                while j < RIGHT_WALL:
+                    ans.append(matrix[i][j])
+                    j += 1
+                i, j = i+1, j-1
+                RIGHT_WALL -= 1
+                direction = DOWN
+            elif direction == DOWN:
+                while i < DOWN_WALL:
+                    ans.append(matrix[i][j])
+                    i += 1
+                i, j = i-1, j-1
+                DOWN_WALL -= 1
+                direction = LEFT
+            elif direction == LEFT:
+                while j > LEFT_WALL:
+                    ans.append(matrix[i][j])
+                    j -= 1
+                i, j = i-1, j+1
+                LEFT_WALL += 1
+                direction = UP
+            else:
+                while i > UP_WALL:
+                    ans.append(matrix[i][j])
+                    i -= 1
+                i, j = i+1, j+1
+                UP_WALL += 1
+                direction = RIGHT
+        
+        return ans 
+        # Time: O(m*n) 
+        # Space: O(1)