Added unique path ii

Author: shichao-an

unique_paths_ii/solution.py

@@ -0,0 +1,28 @@
+class Solution:
+    # @param obstacleGrid, a list of lists of integers
+    # @return an integer
+    def uniquePathsWithObstacles(self, obstacleGrid):
+        n = len(obstacleGrid)
+        m = len(obstacleGrid[0])
+        for i in range(n):
+            for j in range(m):
+                if i == 0:
+                    if obstacleGrid[i][j] == 0:
+                        if j == 0 or (j > 0 and obstacleGrid[i][j - 1] != 0):
+                            obstacleGrid[i][j] = 1
+                    else:
+                        obstacleGrid[i][j] = 0
+                elif j == 0:
+                    if obstacleGrid[i][j] == 0:
+                        # i must be greater that zero here
+                        if obstacleGrid[i - 1][j] != 0:
+                            obstacleGrid[i][j] = 1
+                    else:
+                        obstacleGrid[i][j] = 0
+                else:
+                    if obstacleGrid[i][j] == 0:
+                        obstacleGrid[i][j] = (obstacleGrid[i - 1][j]
+                                              + obstacleGrid[i][j - 1])
+                    else:
+                        obstacleGrid[i][j] = 0
+        return obstacleGrid[n - 1][m - 1]