Given the root node of a binary search tree, return the sum of values of all nodes with a value in the range [low, high].
Example 1:
Input: root = [10,5,15,3,7,null,18], low = 7, high = 15 Output: 32 Example 2:
Input: root = [10,5,15,3,7,13,18,1,null,6], low = 6, high = 10 Output: 23 Constraints:
- The number of nodes in the tree is in the range
[1, 2 * 10^4]. 1 <= Node.val <= 10^51 <= low <= high <= 10^5- All
Node.valare unique.
给定二叉搜索树的根结点 root，返回值位于范围 [low, high] 之间的所有结点的值的和。
- 简单题。因为二叉搜索树的有序性，先序遍历即为有序。遍历过程中判断节点值是否位于区间范围内，在区间内就累加，不在区间内节点就不管。最终输出累加和。
package leetcode import ( "github.com/halfrost/LeetCode-Go/structures" ) // TreeNode definetypeTreeNode= structures.TreeNode/** * Definition for a binary tree node. * type TreeNode struct { * Val int * Left *TreeNode * Right *TreeNode * } */funcrangeSumBST(root*TreeNode, lowint, highint) int { res:=0preOrder(root, low, high, &res) returnres } funcpreOrder(root*TreeNode, low, highint, res*int) { ifroot==nil { return } iflow<=root.Val&&root.Val<=high { *res+=root.Val } preOrder(root.Left, low, high, res) preOrder(root.Right, low, high, res) }