114 lines
3.2 KiB
C
114 lines
3.2 KiB
C
#include <stdlib.h>
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#include <stdio.h>
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#include <time.h>
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#include <string.h>
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#include "numbers.h"
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#include "bintree.h"
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// Hilfsfunktion für qsort und den Binärbaum: Vergleich von unsigned int
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static int compareUnsignedInt(const void *a, const void *b)
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{
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const unsigned int *ua = (const unsigned int *)a;
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const unsigned int *ub = (const unsigned int *)b;
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if (*ua < *ub)
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return -1;
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else if (*ua > *ub)
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return 1;
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else
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return 0;
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}
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// Returns len random numbers between 1 and 2x len in random order which are all different, except for two entries.
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// Returns NULL on errors. Use your implementation of the binary search tree to check for possible duplicates while
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// creating random numbers.
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unsigned int *createNumbers(unsigned int len)
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{
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if (len < 2)
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return NULL;
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unsigned int *numbers = malloc(len * sizeof(unsigned int));
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if (numbers == NULL)
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return NULL;
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// Zufall initialisieren
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srand((unsigned int)time(NULL));
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TreeNode *root = NULL;
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unsigned int i = 0;
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// len-1 verschiedene Zufallszahlen im Bereich [1, 2*len] erzeugen
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while (i < len - 1)
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{
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unsigned int candidate = (unsigned int)(rand() % (2 * len)) + 1;
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int isDuplicate = 0;
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TreeNode *newRoot = addToTree(root, &candidate, sizeof(unsigned int),
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compareUnsignedInt, &isDuplicate);
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if (newRoot == NULL && root == NULL)
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{
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// Speicherfehler beim ersten Einfügen
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clearTree(root);
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free(numbers);
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return NULL;
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}
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root = newRoot;
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if (!isDuplicate)
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{
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numbers[i] = candidate;
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++i;
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}
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// bei Duplikat wird einfach eine neue Zufallszahl generiert
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}
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// Einen zufälligen Eintrag aus den ersten len-1 duplizieren
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unsigned int duplicateIndex = (unsigned int)(rand() % (len - 1));
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numbers[len - 1] = numbers[duplicateIndex];
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// Baum wird nicht mehr benötigt
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clearTree(root);
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// Das Array durchmischen (Fisher-Yates-Shuffle), damit das Duplikat an zufälliger Position steht
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for (unsigned int j = len - 1; j > 0; --j)
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{
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unsigned int k = (unsigned int)(rand() % (j + 1));
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unsigned int tmp = numbers[j];
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numbers[j] = numbers[k];
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numbers[k] = tmp;
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}
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return numbers;
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}
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// Returns only the only number in numbers which is present twice. Returns zero on errors.
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unsigned int getDuplicate(const unsigned int numbers[], unsigned int len)
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{
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if (numbers == NULL || len < 2)
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return 0;
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// Kopie des Arrays anlegen, da qsort in-place sortiert
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unsigned int *copy = malloc(len * sizeof(unsigned int));
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if (copy == NULL)
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return 0;
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memcpy(copy, numbers, len * sizeof(unsigned int));
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// Sortieren mit qsort
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qsort(copy, len, sizeof(unsigned int), compareUnsignedInt);
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// Benachbarte Elemente vergleichen, um das Duplikat zu finden
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unsigned int duplicate = 0;
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for (unsigned int i = 1; i < len; ++i)
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{
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if (copy[i] == copy[i - 1])
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{
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duplicate = copy[i];
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break;
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}
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}
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free(copy);
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return duplicate; // 0 falls kein Duplikat gefunden (Fehlerfall)
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}
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