// File: array_binary_tree.go // Created Time: 2023-07-24 // Author: Reanon (793584285@qq.com) package chapter_tree /* Array-based binary tree class */ type arrayBinaryTree struct { tree []any } /* Constructor */ func newArrayBinaryTree(arr []any) *arrayBinaryTree { return &arrayBinaryTree{ tree: arr, } } /* List capacity */ func (abt *arrayBinaryTree) size() int { return len(abt.tree) } /* Get the value of the node at index i */ func (abt *arrayBinaryTree) val(i int) any { // If the index is out of bounds, return null, representing an empty spot if i < 0 || i >= abt.size() { return nil } return abt.tree[i] } /* Get the index of the left child of the node at index i */ func (abt *arrayBinaryTree) left(i int) int { return 2*i + 1 } /* Get the index of the right child of the node at index i */ func (abt *arrayBinaryTree) right(i int) int { return 2*i + 2 } /* Get the index of the parent of the node at index i */ func (abt *arrayBinaryTree) parent(i int) int { return (i - 1) / 2 } /* Level-order traversal */ func (abt *arrayBinaryTree) levelOrder() []any { var res []any // Traverse array for i := 0; i < abt.size(); i++ { if abt.val(i) != nil { res = append(res, abt.val(i)) } } return res } /* Depth-first traversal */ func (abt *arrayBinaryTree) dfs(i int, order string, res *[]any) { // If it is an empty spot, return if abt.val(i) == nil { return } // Pre-order traversal if order == "pre" { *res = append(*res, abt.val(i)) } abt.dfs(abt.left(i), order, res) // In-order traversal if order == "in" { *res = append(*res, abt.val(i)) } abt.dfs(abt.right(i), order, res) // Post-order traversal if order == "post" { *res = append(*res, abt.val(i)) } } /* Pre-order traversal */ func (abt *arrayBinaryTree) preOrder() []any { var res []any abt.dfs(0, "pre", &res) return res } /* In-order traversal */ func (abt *arrayBinaryTree) inOrder() []any { var res []any abt.dfs(0, "in", &res) return res } /* Post-order traversal */ func (abt *arrayBinaryTree) postOrder() []any { var res []any abt.dfs(0, "post", &res) return res }