-/* PSPP - computes sample statistics.
+/* PSPP - a program for statistical analysis.
Copyright (C) 2007 Free Software Foundation, Inc.
- This program is free software; you can redistribute it and/or
- modify it under the terms of the GNU General Public License as
- published by the Free Software Foundation; either version 2 of the
- License, or (at your option) any later version.
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
- This program is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- 02110-1301, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef LIBPSPP_ABT_H
#define LIBPSPP_ABT_H 1
part of its data as a function of its immediate children's
data. Furthermore, augmented data defined in this way can be
efficiently maintained as the tree changes over time.
-
+
For example, suppose we define the "size" of a node as the sum
of the "size" of its immediate children, plus 1. In such an
annotated BST with height H, we can find the node that would
struct abt_node node; // Embedded binary tree element.
int data; // Primary value.
int count; // Number of nodes in subtree,
- // including this node.
+ // including this node.
};
// Returns the `struct element' that NODE is embedded within.
// strcmp-type return value.
static int
compare_elements (const struct abt_node *a_, const struct abt_node *b_,
- const void *aux)
+ const void *aux)
{
const struct element *a = node_to_element (a_);
const struct element *b = node_to_element (b_);
reaugment_elements (struct abt_node *node_,
const struct abt_node *left,
const struct abt_node *right,
- const void *aux)
+ const void *aux)
{
struct element *node = node_to_element (node_);
node->count = 1;
// Finds and returns the element in ABT that is in the given
// 0-based POSITION in in-order.
static struct element *
- find_by_position (struct abt *abt, int position)
+ find_by_position (struct abt *abt, int position)
{
struct abt_node *p;
- for (p = abt->root; p != NULL; )
+ for (p = abt->root; p != NULL; )
{
int p_pos = p->down[0] ? node_to_element (p->down[0])->count : 0;
if (position == p_pos)
return node_to_element (p);
else if (position < p_pos)
- p = p->down[0];
+ p = p->down[0];
else
{
p = p->down[1];
((STRUCT *) ((char *) (NODE) - offsetof (STRUCT, MEMBER)))
/* Node in an augmented binary tree. */
-struct abt_node
+struct abt_node
{
struct abt_node *up; /* Parent (NULL for root). */
struct abt_node *down[2]; /* Left child, right child. */
const void *aux);
/* An augmented binary tree. */
-struct abt
+struct abt
{
struct abt_node *root; /* Tree's root, NULL if empty. */
abt_compare_func *compare; /* To compare nodes. */