Create 221-Maximal-Square.py

Author: neetcode-gh

221-Maximal-Square.py

@@ -0,0 +1,20 @@
+class Solution:
+    def maximalSquare(self, matrix: List[List[str]]) -> int:
+        ROWS, COLS = len(matrix), len(matrix[0])
+        cache = {} # map each (r, c) -> maxLength of square
+        
+        def helper(r, c):
+            if r >= ROWS or c >= COLS:
+                return 0
+            
+            if (r, c) not in cache:
+                down = helper(r + 1, c)
+                right = helper(r, c + 1)
+                diag = helper(r + 1, c + 1)
+                
+                cache[(r, c)] = 0
+                if matrix[r][c] == "1":
+                    cache[(r, c)] = 1 + min(down, right, diag)
+            return cache[(r, c)]
+        helper(0, 0)
+        return max(cache.values()) ** 2