feat: unique-paths-ii

Author: junbinding

dy.unique-paths-ii.py

@@ -0,0 +1,29 @@
+from typing import List
+
+class Solution:
+    """
+    63. 不同路径 II
+    https://leetcode-cn.com/problems/unique-paths-ii/
+    一个机器人位于一个 m x n 网格的左上角 （起始点在下图中标记为“Start” ）。
+    机器人每次只能向下或者向右移动一步。机器人试图达到网格的右下角（在下图中标记为“Finish”）。
+    现在考虑网格中有障碍物。那么从左上角到右下角将会有多少条不同的路径？
+    """
+    def uniquePathsWithObstacles(self, obstacleGrid: List[List[int]]) -> int:
+        m = len(obstacleGrid)
+        n = len(obstacleGrid[0])
+        res = [[0] * n for _ in range(m)]
+        for i in range(m):
+            for j in range(n):
+                if not obstacleGrid[i][j]:
+                    if i == j == 0:
+                        res[i][j] = 1
+                    else:
+                        a = res[i-1][j] if i != 0 else 0
+                        b = res[i][j-1] if j != 0 else 0
+                        res[i][j] = a + b
+
+        return res[-1][-1]
+
+
+so = Solution()
+print(so.uniquePathsWithObstacles([[0,0,0],[0,1,0],[0,0,0]]))

dy.unique-paths.py

@@ -7,6 +7,14 @@ class Solution:
     问总共有多少条不同的路径？
     """
     def uniquePaths(self, m: int, n: int) -> int:
+        cur = [1] * n
+        for i in range(1, m):
+            for j in range(1, n):
+                cur[j] += cur[j - 1]
+                print('curr', i + 1, j + 1, cur[j-1], cur[j])
+        return cur[-1]
+
+    def uniquePathsByArr(self, m: int, n: int) -> int:
         # 生成缓存数组
         dp = [[1] * n] + [[1] + [0] * (n - 1) for _ in range(m - 1)]
         print(dp)