misc-problem-solutions/src/forfun/graph/invert_binary_tree.cpp at main · oboukli/misc-problem-solutions · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
// Copyright (c) Omar Boukli-Hacene. All rights reserved.
// Distributed under an MIT-style license that can be
// found in the LICENSE file.

// SPDX-License-Identifier: MIT

#include "forfun/graph/invert_binary_tree.hpp"

#include <deque>
#include <utility>

#include "forfun/graph/binary_tree_node.hpp"

namespace forfun::graph::invert_binary_tree {

namespace iterative {

auto invert_binary_tree(binary_tree_node& root) -> void
{
    using std::swap;

    std::deque<binary_tree_node*> tracker{};

    tracker.push_back(&root);

    while (not tracker.empty())
    {
        binary_tree_node* node{tracker.front()};
        tracker.pop_front();

        swap(node->left_node_, node->right_node_);

        if (node->left_node_ != nullptr)
        {
            tracker.push_back(node->left_node_);
        }

        if (node->right_node_ != nullptr)
        {
            tracker.push_back(node->right_node_);
        }
    }
}

} // namespace iterative

namespace recursive {

auto invert_binary_tree(binary_tree_node& root) noexcept -> void
{
    using std::swap;

    swap(root.left_node_, root.right_node_);

    if (root.left_node_ != nullptr)
    {
        invert_binary_tree(*root.left_node_);
    }

    if (root.right_node_ != nullptr)
    {
        invert_binary_tree(*root.right_node_);
    }
}

} // namespace recursive

} // namespace forfun::graph::invert_binary_tree