numbers.c fertig

numbers.c

@@ -14,13 +14,69 @@
 // Returns len random numbers between 1 and 2x len in random order which are all different, except for two entries.
 // Returns NULL on errors. Use your implementation of the binary search tree to check for possible duplicates while
 // creating random numbers.
+
+int compare(const void* a, const void* b) {
+   return (*(unsigned int*)a - *(unsigned int*)b);
+}
+
 unsigned int *createNumbers(unsigned int len)
 {
+  //array erstellen
+  if(len < 2)
+    return NULL;
 
+  unsigned int *arr = malloc(sizeof(unsigned int)*len);
+
+  //sicherstellen dass zahlen einmalig vorkommen
+  srand(time(NULL));
+  for(int i = 0; i < len; i++){
+    while(1){  
+      unsigned int value = (rand() % (2 * len)) + 1;  
+      int alreadyUsed = 0;
+      for(int j = 0; j < i; j++) {
+        if(arr[j] == value) {
+          alreadyUsed = 1;      
+          break;              
+        }
+      }
+      if(!alreadyUsed) {
+        arr[i] = value;         
+        break;                   
+      }
+    }
+  }
+
+  //eine zahl duplizieren und irgendwo hinkopieren
+  int dupIndex = rand() % len;
+  int targetIndex;
+  do{
+    targetIndex = rand() % len;
+  }while (targetIndex == dupIndex);  
+  arr[targetIndex] = arr[dupIndex];
+
+  return arr;
 }
 
 // Returns only the only number in numbers which is present twice. Returns zero on errors.
 unsigned int getDuplicate(const unsigned int numbers[], unsigned int len)
 {
-
+  if(len < 2){
+    return 0;
+  }
+
+  unsigned int *copy = malloc(sizeof(unsigned int)*len);
+
+  memcpy(copy, numbers, len * sizeof(unsigned int));
+
+  qsort(copy, len, sizeof(unsigned int), compare);
+
+  unsigned int duplicate = 0;
+  for(int i = 1; i < len; i++){
+    if(copy[i] == copy[i-1]){
+      duplicate = copy[i];
+      break;
+    }
+  }
+  free(copy);
+  return duplicate;
 }