feat(1386_shift-2d-grid): add py3 soln

1386_shift-2d-grid/python3/simulation.py

@@ -0,0 +1,21 @@
+# Time: O(k · m · n)
+# Space: O(1)
+class Solution:
+    def shiftGrid(self, grid: List[List[int]], k: int) -> List[List[int]]:
+        # Simulation approach, we shift the 2D grid one time, k times
+        # This is acceptable for low values of k (given k <= 100)
+        rows, cols = len(grid), len(grid[0])
+        
+        for _ in range(k):
+            # Assume this is the first shift. When we finish shifting all
+            # elements, the first item in the resulting grid will be the
+            # last item from the original grid.
+            prev = grid[-1][-1]
+            
+            for i in range(rows):
+                for j in range(cols):
+                    tmp = grid[i][j]
+                    grid[i][j] = prev
+                    prev = tmp
+        
+        return grid