create: 0063-unique-paths-ii.py

Author: Amaan6674

Diff for: python/0063-unique-paths-ii.py

@@ -0,0 +1,23 @@
+class Solution:
+    def uniquePathsWithObstacles(self, mat: List[List[int]]) -> int:
+        m = len(mat)
+        n = len(mat[0])
+        prev = [0 for _ in range(n)]
+
+        for i in range(m):
+            curr = [0 for _ in range(n)]
+            for j in range(n):
+                if mat[i][j] == 1:
+                    curr[j] = 0
+                elif i == 0 and j == 0:
+                    curr[j] = 1
+                else:
+                    up = 0
+                    left = 0
+                    if i>0:
+                        up = prev[j]
+                    if j > 0:
+                        left = curr[j-1]
+                    curr[j] = up + left
+            prev = curr
+        return prev[n-1]