128 lines
3.3 KiB
C
128 lines
3.3 KiB
C
#include <string.h>
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#include "stack.h"
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#include "bintree.h"
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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,
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CompareFctType compareFct, int *isDuplicate)
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{
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if (data == NULL || compareFct == NULL)
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return root;
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if (root == NULL)
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{
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// neuer Knoten
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TreeNode *node = malloc(sizeof(TreeNode));
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if (node == NULL)
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return NULL;
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node->data = malloc(dataSize);
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if (node->data == NULL)
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{
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free(node);
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return NULL;
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}
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memcpy(node->data, data, dataSize);
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node->left = NULL;
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node->right = NULL;
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if (isDuplicate != NULL)
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*isDuplicate = 0;
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return node;
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}
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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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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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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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// Element bereits vorhanden
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if (isDuplicate != NULL)
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{
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*isDuplicate = 1;
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// Duplikate werden ignoriert
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}
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else
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{
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// Duplikate dürfen eingefügt werden -> wir hängen sie z.B. links an
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root->left = addToTree(root->left, 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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// Interner Stack für die Traversierung (strtok-ähnliches Verhalten)
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static StackNode *iterStack = NULL;
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// Hilfsfunktion: legt ab start alle linken Knoten auf den Stack
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static void pushLeftPath(TreeNode *start)
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{
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while (start != NULL)
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{
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iterStack = push(iterStack, start);
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start = start->left;
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}
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}
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// Iterates over the tree given by root. Follows the usage of strtok. If tree is NULL,
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// 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.
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// On returning the next element, 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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if (root != NULL)
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{
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// neue Traversierung starten: alten Stack aufräumen
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if (iterStack != NULL)
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{
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clearStack(iterStack);
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iterStack = NULL;
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}
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pushLeftPath(root);
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}
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if (iterStack == NULL)
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return NULL;
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// Nächsten Knoten holen
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TreeNode *node = (TreeNode *)top(iterStack);
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iterStack = pop(iterStack);
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// rechten Teilbaum dieses Knotens auf den Stack bringen
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if (node->right != NULL)
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pushLeftPath(node->right);
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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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clearTree(root->left);
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clearTree(root->right);
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free(root->data);
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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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return 1u + treeSize(root->left) + treeSize(root->right);
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}
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