二分搜索树区间和

lc938. Range Sum of BST.py

@@ -0,0 +1,41 @@
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+
+from bisect import bisect_left
+
+
+class Solution:
+    def dfs(self, root, lst):
+        if not root:
+            return
+        self.dfs(root.left, lst)
+        lst.append(root.val)
+        self.dfs(root.right, lst)
+
+    def rangeSumBST(self, root, L, R):
+        """
+        :type root: TreeNode
+        :type L: int
+        :type R: int
+        :rtype: int
+        """
+        lst = []
+        self.dfs(root, lst)
+        lo = bisect_left(lst, L)
+        hi = bisect_left(lst, R)
+        return sum(lst[lo:hi + 1])
+
+
+root = TreeNode(10)
+root.left = TreeNode(5)
+root.right = TreeNode(15)
+root.left.left = TreeNode(3)
+root.left.right = TreeNode(7)
+L = 7
+R = 15
+s = Solution()
+print(s.rangeSumBST(root, L, R))