139 lines
4.1 KiB
C
139 lines
4.1 KiB
C
#include <string.h>
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#include "stack.h"
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#include "bintree.h"
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//TODO: binären Suchbaum implementieren
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/* * `addToTree`: fügt ein neues Element in den Baum ein (rekursiv),
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* `clearTree`: gibt den gesamten Baum frei (rekursiv),
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* `treeSize`: zählt die Knoten im Baum (rekursiv),
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* `nextTreeData`: Traversierung mit Hilfe des zuvor implementierten Stacks. */
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// Adds a copy of data's pointer destination to the tree using compareFct for ordering. Accepts duplicates
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// if isDuplicate is NULL, otherwise ignores duplicates and sets isDuplicate to 1 (or to 0 if a new entry is added).
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TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize, CompareFctType compareFct, int *isDuplicate)
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{
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// Basisfall: Leerer Baum -> neuen Knoten erstellen
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if (root == NULL)
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{
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TreeNode *newNode = (TreeNode *)malloc(sizeof(TreeNode));
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if (newNode == NULL)
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return NULL;
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// Datenkopie erstellen
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newNode->data = malloc(dataSize);
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if (newNode->data == NULL)
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{
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free(newNode);
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return NULL;
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}
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memcpy(newNode->data, data, dataSize);
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newNode->left = NULL;
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newNode->right = NULL;
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// Neues Element wurde hinzugefügt
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if (isDuplicate != NULL)
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*isDuplicate = 0;
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return newNode;
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}
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// Rekursiver Fall: Vergleiche mit aktuellem Knoten
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int cmp = compareFct(data, root->data);
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if (cmp < 0)
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{
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// Kleiner -> links einfügen
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root->left = addToTree(root->left, data, dataSize, compareFct, isDuplicate);
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}
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else if (cmp > 0)
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{
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// Größer -> rechts einfügen
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root->right = addToTree(root->right, data, dataSize, compareFct, isDuplicate);
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}
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else
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{
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// Gleich -> Duplikat gefunden
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if (isDuplicate != NULL)
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{
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*isDuplicate = 1; // Duplikat erkannt
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// Nichts einfügen, nur isDuplicate setzen
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}
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else
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{
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// Duplikate erlaubt -> füge rechts ein
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root->right = addToTree(root->right, data, dataSize, compareFct, NULL);
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}
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}
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return root;
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}
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// Statischer Stack für nextTreeData (wie bei strtok)
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static StackNode *iteratorStack = NULL;
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// Iterates over the tree given by root. Follows the usage of strtok. If tree is NULL, the next entry of the last tree given is returned in ordering direction.
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// Use your implementation of a stack to organize the iterator. Push the root node and all left nodes first. On returning the next element,
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// push the top node and push all its left nodes.
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void *nextTreeData(TreeNode *root)
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{
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// Neuer Durchlauf: Stack leeren und initialisieren
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if (root != NULL)
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{
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clearStack(iteratorStack);
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iteratorStack = NULL;
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// Wurzel und alle linken Knoten auf den Stack
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TreeNode *current = root;
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while (current != NULL)
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{
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iteratorStack = push(iteratorStack, current);
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current = current->left;
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}
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}
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// Stack leer -> keine weiteren Elemente
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if (iteratorStack == NULL)
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return NULL;
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// Obersten Knoten vom Stack holen
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TreeNode *node = (TreeNode *)top(iteratorStack);
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iteratorStack = pop(iteratorStack);
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// Rechten Teilbaum vorbereiten (alle linken Knoten auf Stack)
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TreeNode *current = node->right;
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while (current != NULL)
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{
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iteratorStack = push(iteratorStack, current);
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current = current->left;
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}
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return node->data;
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}
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// Releases all memory resources (including data copies).
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void clearTree(TreeNode *root)
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{
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if (root == NULL)
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return;
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// Post-Order: Links -> Rechts -> Wurzel
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clearTree(root->left);
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clearTree(root->right);
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// Datenkopie freigeben
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free(root->data);
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// Knoten freigeben
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free(root);
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}
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// Returns the number of entries in the tree given by root.
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unsigned int treeSize(const TreeNode *root)
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{
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if (root == NULL)
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return 0;
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// Rekursiv: 1 (aktueller Knoten) + linker Teilbaum + rechter Teilbaum
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return 1 + treeSize(root->left) + treeSize(root->right);
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}
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