Update solution 0105

Author: halfrost

leetcode/0105.Construct-Binary-Tree-from-Preorder-and-Inorder-Traversal/105. Construct Binary Tree from Preorder and Inorder Traversal.go

@@ -16,7 +16,23 @@ type TreeNode = structures.TreeNode
  * }
  */
 
+// 解法一, 直接传入需要的 slice 范围作为输入, 可以避免申请对应 inorder 索引的内存, 内存使用(leetcode test case) 4.7MB -> 4.3MB.
 func buildTree(preorder []int, inorder []int) *TreeNode {
+	if len(preorder) == 0 {
+		return nil
+	}
+	root := &TreeNode{Val: preorder[0]}
+	for pos, node := range inorder {
+		if node == root.Val {
+			root.Left = buildTree(preorder[1:pos+1], inorder[:pos])
+			root.Right = buildTree(preorder[pos+1:], inorder[pos+1:])
+		}
+	}
+	return root
+}
+
+// 解法二
+func buildTree1(preorder []int, inorder []int) *TreeNode {
 	inPos := make(map[int]int)
 	for i := 0; i < len(inorder); i++ {
 		inPos[inorder[i]] = i

website/content/ChapterFour/0100~0199/0105.Construct-Binary-Tree-from-Preorder-and-Inorder-Traversal.md

@@ -42,6 +42,13 @@ Return the following binary tree:
 
 package leetcode
 
+import (
+	"github.com/halfrost/LeetCode-Go/structures"
+)
+
+// TreeNode define
+type TreeNode = structures.TreeNode
+
 /**
  * Definition for a binary tree node.
  * type TreeNode struct {
@@ -50,7 +57,24 @@ package leetcode
  *     Right *TreeNode
  * }
  */
+
+// 解法一, 直接传入需要的 slice 范围作为输入, 可以避免申请对应 inorder 索引的内存, 内存使用(leetcode test case) 4.7MB -> 4.3MB.
 func buildTree(preorder []int, inorder []int) *TreeNode {
+	if len(preorder) == 0 {
+		return nil
+	}
+	root := &TreeNode{Val: preorder[0]}
+	for pos, node := range inorder {
+		if node == root.Val {
+			root.Left = buildTree(preorder[1:pos+1], inorder[:pos])
+			root.Right = buildTree(preorder[pos+1:], inorder[pos+1:])
+		}
+	}
+	return root
+}
+
+// 解法二
+func buildTree1(preorder []int, inorder []int) *TreeNode {
 	inPos := make(map[int]int)
 	for i := 0; i < len(inorder); i++ {
 		inPos[inorder[i]] = i
@@ -70,20 +94,6 @@ func buildPreIn2TreeDFS(pre []int, preStart int, preEnd int, inStart int, inPos
 	return root
 }
 
-// 解法 2, 直接传入需要的 slice 范围作为输入, 可以避免申请对应 inorder 索引的内存, 内存使用(leetcode test case) 4.7MB -> 4.3MB.
-func buildTree(preorder []int, inorder []int) *TreeNode {
-    if len(preorder) == 0 {
-        return nil
-    }
-    root := &TreeNode{Val:preorder[0]}
-    for pos, node := range inorder {
-        if node == root.Val {
-            root.Left  = buildTree(preorder[1:pos+1], inorder[:pos]) 
-            root.Right = buildTree(preorder[pos+1:], inorder[pos+1:])
-        }
-    }
-    return root
-}
 
 ```