spiral matrix solution

Author: devyejin

spiral-matrix/devyejin.py

@@ -0,0 +1,28 @@
+from typing import List
+
+
+class Solution:
+    def spiralOrder(self, matrix: List[List[int]]) -> List[int]:
+        dr = (0, 1, 0, -1)
+        dc = (1, 0, -1, 0)
+        r, c, d = 0, 0, 0
+
+        n, m = len(matrix), len(matrix[0])
+
+        result = []
+        VISITED = None
+        for _ in range(n * m):
+            result.append(matrix[r][c])
+            matrix[r][c] = VISITED
+
+            nr, nc = r + dr[d], c + dc[d]
+
+            if 0 <= nr < n and 0 <= nc < m and matrix[nr][nc] != VISITED:
+                r, c = nr, nc
+                continue
+
+            d = (d + 1) % 4
+            r += dr[d]
+            c += dc[d]
+
+        return result