Added solution

Author: adityaramkumar

63.py

@@ -0,0 +1,23 @@
+# Runtime: 40 ms, faster than 75.14% of Python3 online submissions for Unique Paths II.
+# Difficulty: Medium
+
+class Solution:
+    def uniquePathsWithObstacles(self, obstacleGrid):
+        """
+        :type obstacleGrid: List[List[int]]
+        :rtype: int
+        """
+        dp_grid = [[0 for i in range(len(obstacleGrid[0]))] 
+                   for j in range(len(obstacleGrid))]
+        dp_grid[len(dp_grid)-1][len(dp_grid[0])-1] = 1
+        
+        for row in range(len(obstacleGrid)-1, -1, -1):
+            for col in range(len(obstacleGrid[row])-1, -1, -1):
+                if obstacleGrid[row][col] == 1:
+                    dp_grid[row][col] = 0
+                    continue
+                if row + 1 < len(obstacleGrid):
+                    dp_grid[row][col] += dp_grid[row+1][col]
+                if col + 1 < len(obstacleGrid[row]):
+                    dp_grid[row][col] += dp_grid[row][col+1]
+        return dp_grid[0][0]