created solution for problem63

Author: dampdigits

problem63/Solution.py

@@ -0,0 +1,21 @@
+class Solution:
+    def uniquePaths(self, m: int, n: int) -> int:
+        # Memoization
+        pathCache = [[0] * n for _ in range(m)]
+
+        def move(i,j):
+            if i == m-1 and j == n-1: return 1
+            if pathCache[i][j]: return pathCache[i][j]
+
+            paths = 0
+            
+            # Go down if row < m-1
+            if i < m-1: paths += move(i+1, j)
+
+            # Go up if column < n-1
+            if j < n-1: paths += move(i, j+1)
+
+            pathCache[i][j] = paths
+            return paths
+
+        return move(0,0)