Merge pull request neetcode-gh#1829 from AP-Repositories/patch-71

Create 0105-construct-binary-tree-from-preorder-and-inorder-traversal.go

go/0105-construct-binary-tree-from-preorder-and-inorder-traversal.go

@@ -0,0 +1,20 @@
+func buildTree(preorder []int, inorder []int) *TreeNode {
+ if len(preorder) == 0 || len(inorder) == 0 {
+ return nil
+ }
+
+ root := &TreeNode{Val: preorder[0]}
+ mid := index(inorder, preorder[0])
+ root.Left = buildTree(preorder[1: mid + 1], inorder[:mid])
+ root.Right = buildTree(preorder[mid + 1:], inorder[mid + 1:])
+ return root
+}
+
+func index(arr []int, val int) int {
+ for i, v := range arr {
+ if v == val {
+ return i
+ }
+ }
+ return -1
+}