Name
Tree::Multi - Multi-way tree in Pure Perl with an even or odd number of keys per node.
Synopsis
Construct and query a multi-way tree in 100% Pure Perl with a choice of an odd or an even numbers of keys per node:
 local $Tree::Multi::numberOfKeysPerNode = 4;  # Number of keys per node - can be even
 my $t = Tree::Multi::new;                     # Construct tree
    $t->insert($_, 2 * $_) for reverse 1..32;  # Load tree in reverse
 is_deeply $t->print, <<END;
15 21 27
  3 6 9 12
    1 2
    4 5
    7 8
    10 11
    13 14
  18
    16 17
    19 20
  24
    22 23
    25 26
  30
    28 29
    31 32
END
 ok  $t->height     ==  3;                     # Height
 ok  $t->find  (16) == 32;                     # Find by key
     $t->delete(16);                           # Delete a key
 ok !$t->find  (16);                           # Key no longer present
 ok  $t->find  (17) == 34;                     # Find by key
 my @k;
 for(my $i = $t->iterator; $i->more; $i->next) # Iterator
  {push @k, $i->key unless $i->key == 17;
  }
 $t->delete($_) for @k;                        # Delete
 ok $t->find(17) == 34 && $t->size == 1;       # Size
Description
Multi-way tree in Pure Perl with an even or odd number of keys per node.
Version "20210629".
The following sections describe the methods in each functional area of this module. For an alphabetic listing of all methods by name see Index.
Multi-way Tree
Create and use a multi-way tree.
root($tree)
Return the root node of a tree.
   Parameter  Description
1  $tree      Tree
Example:
  local $numberOfKeysPerNode = 3; my $N = 13; my $t = new;
  for my $n(1..$N)
   {$t->insert($n, $n);
   }
  ok T($t, <<END);
 4 8
   2
     1
     3
   6
     5
     7
   10 12
     9
     11
     13
END
  is_deeply $t->leftMost ->keys, [1];
  is_deeply $t->rightMost->keys, [13];
  ok $t->leftMost ->leaf;
  ok $t->rightMost->leaf;
  ok $t->root == $t;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
leaf($tree)
Confirm that the tree is a leaf.
   Parameter  Description
1  $tree      Tree
Example:
  local $numberOfKeysPerNode = 3; my $N = 13; my $t = new;
  for my $n(1..$N)
   {$t->insert($n, $n);
   }
  ok T($t, <<END);
 4 8
   2
     1
     3
   6
     5
     7
   10 12
     9
     11
     13
END
  is_deeply $t->leftMost ->keys, [1];
  is_deeply $t->rightMost->keys, [13];
  ok $t->leftMost ->leaf;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  ok $t->rightMost->leaf;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  ok $t->root == $t;
find($root, $key)
Find a key in a tree returning its associated data or undef if the key does not exist.
   Parameter  Description
1  $root      Root of tree
2  $key       Key
Example:
  local $Tree::Multi::numberOfKeysPerNode = 4;                                  # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree
     $t->insert($_, 2 * $_) for reverse 1..32;                                  # Load tree in reverse
  T($t, <<END);
 17 25
   9 13
     3 5 7
       1 2
       4
       6
       8
     11
       10
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     15
       14
       16
   21
     19
       18
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     23
       22
       24
   29
     27
       26
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     31
       30
       32
END
  ok  $t->size       == 32;                                                     # Size
  ok  $t->height     ==  4;                                                     # Height
  ok  $t->delete(16) == 2 * 16;                                                 # Delete a key
  ok !$t->find  (16);                                                           # Key no longer present  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  ok  $t->find  (17) == 34;                                                     # Find by key  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  my @k;
  for(my $i = $t->iterator; $i->more; $i->next)                                 # Iterator
   {push @k, $i->key unless $i->key == 17;
   }
  ok $t->delete($_) == 2 * $_ for @k;                                           # Delete
  ok $t->find(17) == 34 && $t->size == 1;                                       # Size  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  local $Tree::Multi::numberOfKeysPerNode = 3;                                  # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree
     $t->insert($_, $_) for 1..8;
  T($t, <<END, 1);
               4
       2               6
   1       3       5       7   8
END
  local $Tree::Multi::numberOfKeysPerNode = 14;                                 # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree
     $t->insert($_, $_) for 1..15;
  T($t, <<END, 1);
                               8
   1   2   3   4   5   6   7       9   10   11   12   13   14   15
END
leftMost($tree)
Return the left most node below the specified one.
   Parameter  Description
1  $tree      Tree
Example:
  local $numberOfKeysPerNode = 3; my $N = 13; my $t = new;
  for my $n(1..$N)
   {$t->insert($n, $n);
   }
  ok T($t, <<END);
 4 8
   2
     1
     3
   6
     5
     7
   10 12
     9
     11
     13
END
  is_deeply $t->leftMost ->keys, [1];  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  is_deeply $t->rightMost->keys, [13];
  ok $t->leftMost ->leaf;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  ok $t->rightMost->leaf;
  ok $t->root == $t;
rightMost($tree)
Return the right most node below the specified one.
   Parameter  Description
1  $tree      Tree
Example:
  local $numberOfKeysPerNode = 3; my $N = 13; my $t = new;
  for my $n(1..$N)
   {$t->insert($n, $n);
   }
  ok T($t, <<END);
 4 8
   2
     1
     3
   6
     5
     7
   10 12
     9
     11
     13
END
  is_deeply $t->leftMost ->keys, [1];
  is_deeply $t->rightMost->keys, [13];  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  ok $t->leftMost ->leaf;
  ok $t->rightMost->leaf;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  ok $t->root == $t;
height($tree)
Return the height of the tree.
   Parameter  Description
1  $tree      Tree
Example:
  local $Tree::Multi::numberOfKeysPerNode = 3;
  my $t = new;      ok $t->height == 0; ok $t->leftMost->depth == 0; ok $t->size == 0;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(1, 1); ok $t->height == 1; ok $t->leftMost->depth == 1; ok $t->size == 1;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(2, 2); ok $t->height == 1; ok $t->leftMost->depth == 1; ok $t->size == 2;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(3, 3); ok $t->height == 1; ok $t->leftMost->depth == 1; ok $t->size == 3;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(4, 4); ok $t->height == 2; ok $t->leftMost->depth == 2; ok $t->size == 4;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(5, 5); ok $t->height == 2; ok $t->leftMost->depth == 2; ok $t->size == 5;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(6, 6); ok $t->height == 2; ok $t->leftMost->depth == 2; ok $t->size == 6;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(7, 7); ok $t->height == 2; ok $t->leftMost->depth == 2; ok $t->size == 7;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(8, 8); ok $t->height == 3; ok $t->leftMost->depth == 3; ok $t->size == 8;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  T($t, <<END, 1);
               4
       2               6
   1       3       5       7   8
END
depth($tree)
Return the depth of a node within a tree.
   Parameter  Description
1  $tree      Tree
Example:
  local $Tree::Multi::numberOfKeysPerNode = 3;
  my $t = new;      ok $t->height == 0; ok $t->leftMost->depth == 0; ok $t->size == 0;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(1, 1); ok $t->height == 1; ok $t->leftMost->depth == 1; ok $t->size == 1;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(2, 2); ok $t->height == 1; ok $t->leftMost->depth == 1; ok $t->size == 2;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(3, 3); ok $t->height == 1; ok $t->leftMost->depth == 1; ok $t->size == 3;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(4, 4); ok $t->height == 2; ok $t->leftMost->depth == 2; ok $t->size == 4;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(5, 5); ok $t->height == 2; ok $t->leftMost->depth == 2; ok $t->size == 5;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(6, 6); ok $t->height == 2; ok $t->leftMost->depth == 2; ok $t->size == 6;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(7, 7); ok $t->height == 2; ok $t->leftMost->depth == 2; ok $t->size == 7;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(8, 8); ok $t->height == 3; ok $t->leftMost->depth == 3; ok $t->size == 8;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  T($t, <<END, 1);
               4
       2               6
   1       3       5       7   8
END
delete($root, $key)
Find a key in a tree, delete it and return any associated data.
   Parameter  Description
1  $root      Tree root
2  $key       Key
Example:
  local $Tree::Multi::numberOfKeysPerNode = 4;                                  # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree
     $t->insert($_, 2 * $_) for reverse 1..32;                                  # Load tree in reverse
  T($t, <<END);
 17 25
   9 13
     3 5 7
       1 2
       4
       6
       8
     11
       10
       12
     15
       14
       16
   21
     19
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       20
     23
       22
       24
   29
     27
       26
       28
     31
       30
       32
END
  ok  $t->size       == 32;                                                     # Size
  ok  $t->height     ==  4;                                                     # Height
  ok  $t->delete(16) == 2 * 16;                                                 # Delete a key  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  ok !$t->find  (16);                                                           # Key no longer present
  ok  $t->find  (17) == 34;                                                     # Find by key
  my @k;
  for(my $i = $t->iterator; $i->more; $i->next)                                 # Iterator
   {push @k, $i->key unless $i->key == 17;
   }
  ok $t->delete($_) == 2 * $_ for @k;                                           # Delete  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  ok $t->find(17) == 34 && $t->size == 1;                                       # Size
  local $Tree::Multi::numberOfKeysPerNode = 3;                                  # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree
     $t->insert($_, $_) for 1..8;
  T($t, <<END, 1);
               4
       2               6
   1       3       5       7   8
END
  local $Tree::Multi::numberOfKeysPerNode = 14;                                 # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree
     $t->insert($_, $_) for 1..15;
  T($t, <<END, 1);
                               8
   1   2   3   4   5   6   7       9   10   11   12   13   14   15
END
insert($tree, $key, $data)
Insert the specified key and data into a tree.
   Parameter  Description
1  $tree      Tree
2  $key       Key
3  $data      Data
Example:
  local $Tree::Multi::numberOfKeysPerNode = 4;                                  # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree
     $t->insert($_, 2 * $_) for reverse 1..32;                                  # Load tree in reverse  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  T($t, <<END);
 17 25
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       1 2
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END
  ok  $t->size       == 32;                                                     # Size
  ok  $t->height     ==  4;                                                     # Height
  ok  $t->delete(16) == 2 * 16;                                                 # Delete a key
  ok !$t->find  (16);                                                           # Key no longer present
  ok  $t->find  (17) == 34;                                                     # Find by key
  my @k;
  for(my $i = $t->iterator; $i->more; $i->next)                                 # Iterator
   {push @k, $i->key unless $i->key == 17;
   }
  ok $t->delete($_) == 2 * $_ for @k;                                           # Delete
  ok $t->find(17) == 34 && $t->size == 1;                                       # Size
  local $Tree::Multi::numberOfKeysPerNode = 3;                                  # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree
     $t->insert($_, $_) for 1..8;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  T($t, <<END, 1);
               4
       2               6
   1       3       5       7   8
END
  local $Tree::Multi::numberOfKeysPerNode = 14;                                 # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree
     $t->insert($_, $_) for 1..15;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  T($t, <<END, 1);
                               8
   1   2   3   4   5   6   7       9   10   11   12   13   14   15
END
iterator($tree)
Make an iterator for a tree.
   Parameter  Description
1  $tree      Tree
Example:
  local $numberOfKeysPerNode = 3; my $N = 256; my $e = 0;  my $t = new;
  for my $n(0..$N)
   {$t->insert($n, $n);
    my @n; for(my $i = $t->iterator; $i->more; $i->next) {push @n, $i->key}  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
    ++$e unless dump(\@n) eq dump [0..$n];
   }
  is_deeply $e, 0;
  local $Tree::Multi::numberOfKeysPerNode = 4;                                  # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree
     $t->insert($_, 2 * $_) for reverse 1..32;                                  # Load tree in reverse
  T($t, <<END);
 17 25
   9 13
     3 5 7
       1 2
       4
       6
       8
     11
       10
       12
     15
       14
       16
   21
     19
       18
       20
     23
       22
       24
   29
     27
       26
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     31
       30
       32
END
  ok  $t->size       == 32;                                                     # Size
  ok  $t->height     ==  4;                                                     # Height
  ok  $t->delete(16) == 2 * 16;                                                 # Delete a key
  ok !$t->find  (16);                                                           # Key no longer present
  ok  $t->find  (17) == 34;                                                     # Find by key
  my @k;
  for(my $i = $t->iterator; $i->more; $i->next)                                 # Iterator  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
   {push @k, $i->key unless $i->key == 17;
   }
  ok $t->delete($_) == 2 * $_ for @k;                                           # Delete
  ok $t->find(17) == 34 && $t->size == 1;                                       # Size
  local $Tree::Multi::numberOfKeysPerNode = 3;                                  # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree
     $t->insert($_, $_) for 1..8;
  T($t, <<END, 1);
               4
       2               6
   1       3       5       7   8
END
  local $Tree::Multi::numberOfKeysPerNode = 14;                                 # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree
     $t->insert($_, $_) for 1..15;
  T($t, <<END, 1);
                               8
   1   2   3   4   5   6   7       9   10   11   12   13   14   15
END
Tree::Multi::Iterator::next($iter)
Find the next key.
   Parameter  Description
1  $iter      Iterator
Example:
  local $numberOfKeysPerNode = 3; my $N = 256; my $e = 0;  my $t = new;
  for my $n(0..$N)
   {$t->insert($n, $n);
    my @n; for(my $i = $t->iterator; $i->more; $i->next) {push @n, $i->key}
    ++$e unless dump(\@n) eq dump [0..$n];
   }
  is_deeply $e, 0;
reverseIterator($tree)
Create a reverse iterator for a tree.
   Parameter  Description
1  $tree      Tree
Example:
  local $numberOfKeysPerNode = 3; my $N = 64;  my $e = 0;
  for my $n(0..$N)
   {my $t = new;
    for my $i(0..$n)
     {$t->insert($i, $i);
     }
    my @n;
    for(my $i = $t->reverseIterator; $i->less; $i->prev)  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
     {push @n, $i->key;
     }
    ++$e unless dump(\@n) eq dump [reverse 0..$n];
   }
  is_deeply $e, 0;
Tree::Multi::ReverseIterator::prev($iter)
Find the previous key.
   Parameter  Description
1  $iter      Iterator
Example:
  local $numberOfKeysPerNode = 3; my $N = 64;  my $e = 0;
  for my $n(0..$N)
   {my $t = new;
    for my $i(0..$n)
     {$t->insert($i, $i);
     }
    my @n;
    for(my $i = $t->reverseIterator; $i->less; $i->prev)
     {push @n, $i->key;
     }
    ++$e unless dump(\@n) eq dump [reverse 0..$n];
   }
  is_deeply $e, 0;
flat($tree, @title)
Print the keys in a tree from left right to make it easier to visualize the structure of the tree.
   Parameter  Description
1  $tree      Tree
2  @title     Title
Example:
  local $Tree::Multi::numberOfKeysPerNode = 3;
  my $t = new;      ok $t->height == 0; ok $t->leftMost->depth == 0; ok $t->size == 0;
  $t->insert(1, 1); ok $t->height == 1; ok $t->leftMost->depth == 1; ok $t->size == 1;
  $t->insert(2, 2); ok $t->height == 1; ok $t->leftMost->depth == 1; ok $t->size == 2;
  $t->insert(3, 3); ok $t->height == 1; ok $t->leftMost->depth == 1; ok $t->size == 3;
  $t->insert(4, 4); ok $t->height == 2; ok $t->leftMost->depth == 2; ok $t->size == 4;
  $t->insert(5, 5); ok $t->height == 2; ok $t->leftMost->depth == 2; ok $t->size == 5;
  $t->insert(6, 6); ok $t->height == 2; ok $t->leftMost->depth == 2; ok $t->size == 6;
  $t->insert(7, 7); ok $t->height == 2; ok $t->leftMost->depth == 2; ok $t->size == 7;
  $t->insert(8, 8); ok $t->height == 3; ok $t->leftMost->depth == 3; ok $t->size == 8;
  T($t, <<END, 1);
               4
       2               6
   1       3       5       7   8
END
print($tree, $i)
Print the keys in a tree optionally marking the active key.
   Parameter  Description
1  $tree      Tree
2  $i         Optional index of active key
Example:
  local $Tree::Multi::numberOfKeysPerNode = 4;                                  # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree
     $t->insert($_, 2 * $_) for reverse 1..32;                                  # Load tree in reverse
  T($t, <<END);
 17 25
   9 13
     3 5 7
       1 2
       4
       6
       8
     11
       10
       12
     15
       14
       16
   21
     19
       18
       20
     23
       22
       24
   29
     27
       26
       28
     31
       30
       32
END
  ok  $t->size       == 32;                                                     # Size
  ok  $t->height     ==  4;                                                     # Height
  ok  $t->delete(16) == 2 * 16;                                                 # Delete a key
  ok !$t->find  (16);                                                           # Key no longer present
  ok  $t->find  (17) == 34;                                                     # Find by key
  my @k;
  for(my $i = $t->iterator; $i->more; $i->next)                                 # Iterator
   {push @k, $i->key unless $i->key == 17;
   }
  ok $t->delete($_) == 2 * $_ for @k;                                           # Delete
  ok $t->find(17) == 34 && $t->size == 1;                                       # Size
  local $Tree::Multi::numberOfKeysPerNode = 3;                                  # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree
     $t->insert($_, $_) for 1..8;
  T($t, <<END, 1);
               4
       2               6
   1       3       5       7   8
END
  local $Tree::Multi::numberOfKeysPerNode = 14;                                 # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree
     $t->insert($_, $_) for 1..15;
  T($t, <<END, 1);
                               8
   1   2   3   4   5   6   7       9   10   11   12   13   14   15
END
size($tree)
Count the number of keys in a tree.
   Parameter  Description
1  $tree      Tree
Example:
  local $Tree::Multi::numberOfKeysPerNode = 3;
  my $t = new;      ok $t->height == 0; ok $t->leftMost->depth == 0; ok $t->size == 0;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(1, 1); ok $t->height == 1; ok $t->leftMost->depth == 1; ok $t->size == 1;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(2, 2); ok $t->height == 1; ok $t->leftMost->depth == 1; ok $t->size == 2;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(3, 3); ok $t->height == 1; ok $t->leftMost->depth == 1; ok $t->size == 3;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(4, 4); ok $t->height == 2; ok $t->leftMost->depth == 2; ok $t->size == 4;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(5, 5); ok $t->height == 2; ok $t->leftMost->depth == 2; ok $t->size == 5;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(6, 6); ok $t->height == 2; ok $t->leftMost->depth == 2; ok $t->size == 6;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(7, 7); ok $t->height == 2; ok $t->leftMost->depth == 2; ok $t->size == 7;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  $t->insert(8, 8); ok $t->height == 3; ok $t->leftMost->depth == 3; ok $t->size == 8;  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
  T($t, <<END, 1);
               4
       2               6
   1       3       5       7   8
END
Hash Definitions
Tree::Multi Definition
Iterator
Output fields
count
Counter
data
Data at this position
key
Key at this position
keys
Array of key items for this node
less
Iteration not yet finished
more
Iteration not yet finished
node
Current node within tree
pos
Current position within node
tree
Tree we are iterating over
up
Parent node
Private Methods
new()
Create a new multi-way tree node.
Example:
  local $Tree::Multi::numberOfKeysPerNode = 4;                                  # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
     $t->insert($_, 2 * $_) for reverse 1..32;                                  # Load tree in reverse
  T($t, <<END);
 17 25
   9 13
     3 5 7
       1 2
       4
       6
       8
     11
       10
       12
     15
       14
       16
   21
     19
       18
       20
     23
       22
       24
   29
     27
       26
       28
     31
       30
       32
END
  ok  $t->size       == 32;                                                     # Size
  ok  $t->height     ==  4;                                                     # Height
  ok  $t->delete(16) == 2 * 16;                                                 # Delete a key
  ok !$t->find  (16);                                                           # Key no longer present
  ok  $t->find  (17) == 34;                                                     # Find by key
  my @k;
  for(my $i = $t->iterator; $i->more; $i->next)                                 # Iterator
   {push @k, $i->key unless $i->key == 17;
   }
  ok $t->delete($_) == 2 * $_ for @k;                                           # Delete
  ok $t->find(17) == 34 && $t->size == 1;                                       # Size
  local $Tree::Multi::numberOfKeysPerNode = 3;                                  # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
     $t->insert($_, $_) for 1..8;
  T($t, <<END, 1);
               4
       2               6
   1       3       5       7   8
END
  local $Tree::Multi::numberOfKeysPerNode = 14;                                 # Number of keys per node - can be even
  my $t = Tree::Multi::new;                                                     # Construct tree  # 𝗘𝘅𝗮𝗺𝗽𝗹𝗲
     $t->insert($_, $_) for 1..15;
  T($t, <<END, 1);
                               8
   1   2   3   4   5   6   7       9   10   11   12   13   14   15
END
minimumNumberOfKeys()
Minimum number of keys per node.
maximumNumberOfKeys()
Maximum number of keys per node.
maximumNumberOfNodes()
Maximum number of children per parent.
full($tree)
Confirm that a node is full.
   Parameter  Description
1  $tree      Tree
halfFull($tree)
Confirm that a node is half full.
   Parameter  Description
1  $tree      Tree
reUp($tree, $children)
Reconnect the children to their new parent.
   Parameter  Description
1  $tree      Tree
2  $children  Children
splitFullNode($isRoot, $isLeaf, $node)
Split a node if it is full.
   Parameter  Description
1  $isRoot    Known to be the root if true
2  $isLeaf    Known to be a leaf if true
3  $node      Node to split
findAndSplit($root, $key)
Find a key in a tree splitting full nodes along the path to the key.
   Parameter  Description
1  $root      Root of tree
2  $key       Key
indexInParent($tree)
Get the index of a node in its parent.
   Parameter  Description
1  $tree      Tree
fillFromLeftOrRight($node, $dir)
Fill a node from the specified sibling.
   Parameter  Description
1  $node      Node to fill
2  $dir       Node to fill from 0 for left or 1 for right
mergeWithLeftOrRight($n, $dir)
Merge two adjacent nodes.
   Parameter  Description
1  $n         Node to merge into
2  $dir       Node to merge is on right if 1 else left
merge($tree)
Merge the current node with its sibling.
   Parameter  Description
1  $tree      Tree
mergeOrFill($tree)
Make a node larger than a half node.
   Parameter  Description
1  $tree      Tree
deleteLeafKey($tree, $i)
Delete a key in a leaf.
   Parameter  Description
1  $tree      Tree
2  $i         Index to delete at
deleteKey($tree, $i)
Delete a key.
   Parameter  Description
1  $tree      Tree
2  $i         Index to delete at
T($tree, $expected, $flat)
Print a tree to the log file and check it against the expected result
   Parameter  Description
1  $tree      Tree
2  $expected  Expected print
3  $flat      Optionally print in flat mode if true
F($tree, $expected)
Print a tree flatly to the log file and check its result
   Parameter  Description
1  $tree      Tree
2  $expected  Expected print
disordered($n, $N)
Disordered but stable insertions
   Parameter  Description
1  $n         Keys per node
2  $N         Nodes
disorderedCheck($t, $n, $N)
Check disordered insertions
   Parameter  Description
1  $t         Tree to check
2  $n         Keys per node
3  $N         Nodes
randomCheck($n, $N, $T)
Random insertions
   Parameter  Description
1  $n         Keys per node
2  $N         Log 10 nodes
3  $T         Log 10 number of tests
Index
1 delete - Find a key in a tree, delete it and return any associated data.
2 deleteKey - Delete a key.
3 deleteLeafKey - Delete a key in a leaf.
4 depth - Return the depth of a node within a tree.
5 disordered - Disordered but stable insertions
6 disorderedCheck - Check disordered insertions
7 F - Print a tree flatly to the log file and check its result
8 fillFromLeftOrRight - Fill a node from the specified sibling.
9 find - Find a key in a tree returning its associated data or undef if the key does not exist.
10 findAndSplit - Find a key in a tree splitting full nodes along the path to the key.
11 flat - Print the keys in a tree from left right to make it easier to visualize the structure of the tree.
12 full - Confirm that a node is full.
13 halfFull - Confirm that a node is half full.
14 height - Return the height of the tree.
15 indexInParent - Get the index of a node in its parent.
16 insert - Insert the specified key and data into a tree.
17 iterator - Make an iterator for a tree.
18 leaf - Confirm that the tree is a leaf.
19 leftMost - Return the left most node below the specified one.
20 maximumNumberOfKeys - Maximum number of keys per node.
21 maximumNumberOfNodes - Maximum number of children per parent.
22 merge - Merge the current node with its sibling.
23 mergeOrFill - Make a node larger than a half node.
24 mergeWithLeftOrRight - Merge two adjacent nodes.
25 minimumNumberOfKeys - Minimum number of keys per node.
26 new - Create a new multi-way tree node.
27 print - Print the keys in a tree optionally marking the active key.
28 randomCheck - Random insertions
29 reUp - Reconnect the children to their new parent.
30 reverseIterator - Create a reverse iterator for a tree.
31 rightMost - Return the right most node below the specified one.
32 root - Return the root node of a tree.
33 size - Count the number of keys in a tree.
34 splitFullNode - Split a node if it is full.
35 T - Print a tree to the log file and check it against the expected result
36 Tree::Multi::Iterator::next - Find the next key.
37 Tree::Multi::ReverseIterator::prev - Find the previous key.
Installation
This module is written in 100% Pure Perl and, thus, it is easy to read, comprehend, use, modify and install via cpan:
sudo cpan install Tree::Multi
Author
Copyright
Copyright (c) 2016-2021 Philip R Brenan.
This module is free software. It may be used, redistributed and/or modified under the same terms as Perl itself.