111 lines
3.0 KiB
C
111 lines
3.0 KiB
C
#include <stdlib.h>
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#include <string.h>
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#include "stack.h"
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#include "bintree.h"
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// internal helper to push node and all its left descendants onto iterator stack
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static void bintree_pushLefts(StackNode **iterStackPtr, TreeNode *n)
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{
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while(n != NULL)
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{
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*iterStackPtr = push(*iterStackPtr, n);
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n = n->left;
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}
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}
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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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if(isDuplicate != NULL)
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*isDuplicate = 0;
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if(root == NULL)
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{
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TreeNode *node = (TreeNode *)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 = node->right = NULL;
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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 // equal
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{
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if(isDuplicate != NULL)
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{
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*isDuplicate = 1;
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// do not insert duplicate
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}
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else
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{
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// duplicates allowed -> insert into right subtree
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root->right = addToTree(root->right, data, dataSize, compareFct, isDuplicate);
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}
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}
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return root;
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}
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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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static StackNode *iterStack = NULL;
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// If a new tree root is provided -> reset iterator
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if(root != NULL)
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{
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clearStack(iterStack);
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iterStack = NULL;
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bintree_pushLefts(&iterStack, root);
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}
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if(iterStack == NULL)
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return NULL;
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TreeNode *node = (TreeNode *)top(iterStack);
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iterStack = pop(iterStack);
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if(node->right != NULL)
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bintree_pushLefts(&iterStack, 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 1 + treeSize(root->left) + treeSize(root->right);
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} |