1038. 从二叉搜索树到更大和树

1038. 从二叉搜索树到更大和树

• 难度: medium
• 原始链接: https://leetcode.cn/problems/binary-search-tree-to-greater-sum-tree
• 标签: 中序遍历

解法一: 中序遍历

go

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func bstToGst(root *TreeNode) *TreeNode {
    var dfs func (node *TreeNode, sum int) int
    dfs = func (node *TreeNode, sum int) int {
        if node == nil {
            return sum
        }
        node.Val += dfs(node.Right, sum)
        return dfs(node.Left, node.Val)
    }
    dfs(root, 0)
    return root
}