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	`1`	`+`
	`2`	`+# 0098.validate-binary-search-tree`
	`3`	+```text
	`4`	`+`
	`5`	`+给定一个二叉树,判断其是否是一个有效的二叉搜索树。`
	`6`	`+`
	`7`	`+假设一个二叉搜索树具有如下特征:`
	`8`	`+`
	`9`	`+节点的左子树只包含小于当前节点的数。`
	`10`	`+节点的右子树只包含大于当前节点的数。`
	`11`	`+所有左子树和右子树自身必须也是二叉搜索树。`
	`12`	`+`
	`13`	`+示例 1:`
	`14`	`+`
	`15`	`+输入:`
	`16`	`+ 2`
	`17`	`+ / \`
	`18`	`+ 1 3`
	`19`	`+输出: true`
	`20`	`+示例 2:`
	`21`	`+`
	`22`	`+输入:`
	`23`	`+ 5`
	`24`	`+ / \`
	`25`	`+ 1 4`
	`26`	`+ / \`
	`27`	`+ 3 6`
	`28`	`+输出: false`
	`29`	`+解释: 输入为: [5,1,4,null,null,3,6]。`
	`30`	`+ 根节点的值为 5 ,但是其右子节点值为 4 。`
	`31`	`+`
	`32`	`+来源:力扣(LeetCode)`
	`33`	`+链接:https://leetcode-cn.com/problems/validate-binary-search-tree`
	`34`	`+著作权归领扣网络所有。商业转载请联系官方授权,非商业转载请注明出处。`
	`35`	+```

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	`1`	`+package tree`
	`2`	`+`
	`3`	`+import (`
	`4`	`+ "fmt"`
	`5`	`+ "github.com/itcuihao/leetcode-go/structure"`
	`6`	`+)`
	`7`	`+`
	`8`	`+func Run() {`
	`9`	`+ root := structure.BinaryTree98`
	`10`	`+ b := isValidBST(root)`
	`11`	`+ fmt.Println(b)`
	`12`	`+}`
	`13`	`+`
	`14`	`+/**`
	`15`	`+ * Definition for a binary tree node.`
	`16`	`+ * type TreeNode struct {`
	`17`	`+ * Val int`
	`18`	`+ * Left *TreeNode`
	`19`	`+ * Right *TreeNode`
	`20`	`+ * }`
	`21`	`+ */`
	`22`	`+func isValidBST(root *structure.TreeNode) bool {`
	`23`	`+ res := traverse(root)`
	`24`	`+ if len(res) <= 1 {`
	`25`	`+ return true`
	`26`	`+ }`
	`27`	`+ tmp := res[0]`
	`28`	`+ for i := 1; i < len(res); i++ {`
	`29`	`+ if res[i] <= tmp {`
	`30`	`+ return false`
	`31`	`+ }`
	`32`	`+ tmp = res[i]`
	`33`	`+ }`
	`34`	`+ return true`
	`35`	`+}`
	`36`	`+`
	`37`	`+// 中序遍历获取有序数组`
	`38`	`+func traverse(root *structure.TreeNode) []int {`
	`39`	`+ res := make([]int, 0)`
	`40`	`+ if root == nil {`
	`41`	`+ return res`
	`42`	`+ }`
	`43`	`+ res = append(res, traverse(root.Left)...)`
	`44`	`+ res = append(res, root.Val)`
	`45`	`+ res = append(res, traverse(root.Right)...)`
	`46`	`+ return res`
	`47`	`+}`

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