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solved: 106. Construct Binary Tree from Inorder and Postorder Traversal

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src/0101-0200/106 - Construct Binary Tree from Inorder and Postorder Traversal
- construct_binary_tree_from_inorder_and_postorder_traversal.go

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	`1`	`+package main`
	`2`	`+`
	`3`	`+// Definition for a binary tree node.`
	`4`	`+type TreeNode struct {`
	`5`	`+ Val int`
	`6`	`+ Left *TreeNode`
	`7`	`+ Right *TreeNode`
	`8`	`+}`
	`9`	`+`
	`10`	`+func buildTree(inorder []int, postorder []int) *TreeNode {`
	`11`	`+ mapInOrder := make(map[int]int)`
	`12`	`+`
	`13`	`+ for i, v := range inorder {`
	`14`	`+ mapInOrder[v] = i`
	`15`	`+ }`
	`16`	`+`
	`17`	`+ var helper func(int, int) *TreeNode`
	`18`	`+ helper = func(left, right int) *TreeNode {`
	`19`	`+ if left > right {`
	`20`	`+ return nil`
	`21`	`+ }`
	`22`	`+`
	`23`	`+ pop := postorder[len(postorder)-1]`
	`24`	`+ postorder = postorder[:len(postorder)-1]`
	`25`	`+`
	`26`	`+ root := &TreeNode{Val: pop}`
	`27`	`+ mid := mapInOrder[pop]`
	`28`	`+ root.Right = helper(mid+1, right)`
	`29`	`+ root.Left = helper(left, mid-1)`
	`30`	`+`
	`31`	`+ return root`
	`32`	`+ }`
	`33`	`+`
	`34`	`+ return helper(0, len(inorder)-1)`
	`35`	`+}`

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