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57 lines
2.0 KiB
57 lines
2.0 KiB
// File: binary_tree_bfs.zig
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// Created Time: 2023-01-15
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// Author: codingonion (coderonion@gmail.com)
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const std = @import("std");
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const inc = @import("include");
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// 層序走訪
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fn levelOrder(comptime T: type, mem_allocator: std.mem.Allocator, root: *inc.TreeNode(T)) !std.ArrayList(T) {
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// 初始化佇列，加入根節點
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const L = std.TailQueue(*inc.TreeNode(T));
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var queue = L{};
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var root_node = try mem_allocator.create(L.Node);
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root_node.data = root;
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queue.append(root_node);
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// 初始化一個串列，用於儲存走訪序列
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var list = std.ArrayList(T).init(std.heap.page_allocator);
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while (queue.len > 0) {
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var queue_node = queue.popFirst().?; // 隊列出隊
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var node = queue_node.data;
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try list.append(node.val); // 儲存節點值
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if (node.left != null) {
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var tmp_node = try mem_allocator.create(L.Node);
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tmp_node.data = node.left.?;
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queue.append(tmp_node); // 左子節點入列
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}
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if (node.right != null) {
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var tmp_node = try mem_allocator.create(L.Node);
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tmp_node.data = node.right.?;
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queue.append(tmp_node); // 右子節點入列
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}
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}
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return list;
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}
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// Driver Code
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pub fn main() !void {
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// 初始化記憶體分配器
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var mem_arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
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defer mem_arena.deinit();
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const mem_allocator = mem_arena.allocator();
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// 初始化二元樹
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// 這裡藉助了一個從陣列直接生成二元樹的函式
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var nums = [_]i32{1, 2, 3, 4, 5, 6, 7};
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var root = try inc.TreeUtil.arrToTree(i32, mem_allocator, &nums);
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std.debug.print("初始化二元樹\n", .{});
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try inc.PrintUtil.printTree(root, null, false);
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// 層序走訪
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var list = try levelOrder(i32, mem_allocator, root.?);
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defer list.deinit();
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std.debug.print("\n層序走訪的節點列印序列 = ", .{});
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inc.PrintUtil.printList(i32, list);
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_ = try std.io.getStdIn().reader().readByte();
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} |