mirror of
https://github.com/halfrost/LeetCode-Go.git
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62 lines
1.3 KiB
Go
62 lines
1.3 KiB
Go
package leetcode
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import (
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"github.com/halfrost/LeetCode-Go/structures"
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)
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// TreeNode define
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type TreeNode = structures.TreeNode
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/**
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* Definition for a binary tree node.
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* type TreeNode struct {
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* Val int
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* Left *TreeNode
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* Right *TreeNode
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* }
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*/
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// 解法一 链表思想
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func increasingBST(root *TreeNode) *TreeNode {
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var head = &TreeNode{}
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tail := head
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recBST(root, tail)
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return head.Right
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}
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func recBST(root, tail *TreeNode) *TreeNode {
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if root == nil {
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return tail
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}
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tail = recBST(root.Left, tail)
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root.Left = nil // 切断 root 与其 Left 的连接，避免形成环
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tail.Right, tail = root, root // 把 root 接上 tail，并保持 tail 指向尾部
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tail = recBST(root.Right, tail)
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return tail
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}
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// 解法二 模拟
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func increasingBST1(root *TreeNode) *TreeNode {
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list := []int{}
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inorder(root, &list)
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if len(list) == 0 {
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return root
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}
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newRoot := &TreeNode{Val: list[0], Left: nil, Right: nil}
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cur := newRoot
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for index := 1; index < len(list); index++ {
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tmp := &TreeNode{Val: list[index], Left: nil, Right: nil}
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cur.Right = tmp
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cur = tmp
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}
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return newRoot
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}
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func inorder(root *TreeNode, output *[]int) {
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if root != nil {
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inorder(root.Left, output)
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*output = append(*output, root.Val)
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inorder(root.Right, output)
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}
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}
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