/**
* Definition for a binary tree node.
* type TreeNode struct {
* Val int
* Left *TreeNode
* Right *TreeNode
* }
*/
func buildTree(preorder []int, inorder []int) *TreeNode {
if len(preorder)==0{
return nil
}
root:=&TreeNode{preorder[0],nil,nil}
i:=0
for ;i<len(inorder);i++{
if inorder[i]==preorder[0]{
break
}
}
root.Left=buildTree(preorder[1:len(inorder[:i])+1],inorder[:i])
root.Right=buildTree(preorder[len(inorder[:i])+1:],inorder[i+1:])
return root
}