37 lines
565 B
Go
37 lines
565 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 isValidBST(root *TreeNode) bool {
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var helper func(root *TreeNode) []int
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helper = func(root *TreeNode) []int {
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if root == nil {
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return []int{}
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}
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tmp := make([]int, 0)
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tmp = append(tmp, helper(root.Left)...)
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tmp = append(tmp, root.Val)
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tmp = append(tmp, helper(root.Right)...)
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return tmp
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}
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res := helper(root)
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for i := 0; i < len(res); i++ {
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if i == 0 {
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continue
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}
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if res[i-1] >= res[i] {
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return false
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}
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}
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return true
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}
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