course

Author: genkimaru

Diff for: src/graph/course.py

@@ -25,4 +25,4 @@ def canFinish(numCourses, prerequisites):
 # 示例
 ## [a , b] ,可以表示为 b -> a
 print(canFinish(2, [[1, 0]]))  # 返回 True
-print(canFinish(2, [[1, 0], [0, 1]]))  # 返回 False
+print(canFinish(2, [[1, 0], [0, 1]]))  # 返回 False

Diff for: src/graph/course_v2.py

@@ -0,0 +1,46 @@
+from collections import deque
+from typing import List
+class Solution:
+    # 使用 拓扑排序 验证一个图是否是 DAG
+    _prev_indegree = []
+    def canFinish( self , courseNums: int, arr: List[List[int]]) -> bool:
+        ## 设置入度数组
+        indegree = [ 0  for _ in range(courseNums)] 
+
+        if arr:
+            for pair in arr:
+                indegree[pair[0]] = indegree[pair[0]] + 1
+        else:
+            return True
+        
+        result = self.is_zero(indegree)
+
+        if result:
+            return True
+        else:
+            if self.is_not_changed(indegree):
+                return False
+            else:
+                new_arr = []
+                for pair in arr:
+                    if indegree[pair[1]] != 0:
+                        new_arr.append(pair)
+                self._prev_indegree = indegree
+                return self.canFinish(courseNums , new_arr)
+
+    def is_zero(self , indegree):
+        return len(list(filter(lambda x : x == 0  , indegree))) == len(indegree)
+    
+    def is_not_changed(self , indegree):
+        if self._prev_indegree:
+            return indegree == self._prev_indegree
+        else:
+            return False
+
+# 示例
+## [a , b] ,可以表示为 b -> a
+# print(canFinish(2, [[1, 0]]))  # 返回 True
+# print(Solution().canFinish(2, [[1, 0], [0, 1]]))  # 返回 False
+# r = canFinish(6 , [[0,1],[0,2],[1,2],[2,0],[0,4],[3,5]])
+
+# print(Solution().canFinish(20 , [[0,10],[3,18],[5,5],[6,11],[11,14],[13,1],[15,1],[17,4]]))

Diff for: src/slidingwindow/min_window.py

@@ -38,6 +38,6 @@ def min_window(s, t):
     return s[min_start:min_start+min_len]
 
 # 测试
-s = "ADOBECODEBANC"
-t = "ABC"
+s = "a"
+t = "aa"
 print(min_window(s, t))  # 输出"BANC"