47 lines
746 B
Go
47 lines
746 B
Go
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package main
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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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func main() {
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}
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func buildTree(preorder []int, inorder []int) *TreeNode {
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var builder func(p []int, in []int) *TreeNode
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builder = func(p []int, in []int) *TreeNode {
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if len(in) == 0 || len(p) == 0 {
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return nil
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}
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rootnum := p[0]
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value := -1
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for i := 0; i < len(in); i++ {
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if in[i] == rootnum {
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value = i
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}
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}
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var left []int
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var right []int
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if value != -1 {
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left = in[:value]
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right = in[value+1:]
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} else {
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return nil
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}
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tmp := &TreeNode{
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Val: rootnum,
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Left: builder(p[1:1+len(left)], left),
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Right: builder(p[1+len(left):], right),
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}
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return tmp
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}
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res := builder(preorder, inorder)
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return res
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}
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