43 lines
1.2 KiB
Swift
43 lines
1.2 KiB
Swift
/**
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* File: binary_tree_bfs.swift
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* Created Time: 2023-01-18
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* Author: nuomi1 (nuomi1@qq.com)
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*/
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import utils
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/* Level-order traversal */
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func levelOrder(root: TreeNode) -> [Int] {
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// Initialize queue, add root node
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var queue: [TreeNode] = [root]
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// Initialize a list to store the traversal sequence
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var list: [Int] = []
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while !queue.isEmpty {
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let node = queue.removeFirst() // Queue dequeues
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list.append(node.val) // Save node value
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if let left = node.left {
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queue.append(left) // Left child node enqueues
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}
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if let right = node.right {
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queue.append(right) // Right child node enqueues
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}
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}
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return list
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}
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@main
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enum BinaryTreeBFS {
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/* Driver Code */
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static func main() {
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/* Initialize binary tree */
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// Use a specific function to convert an array into a binary tree
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let node = TreeNode.listToTree(arr: [1, 2, 3, 4, 5, 6, 7])!
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print("\nInitialize binary tree\n")
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PrintUtil.printTree(root: node)
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/* Level-order traversal */
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let list = levelOrder(root: node)
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print("\nSequence of nodes in level-order traversal = \(list)")
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}
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}
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