Kollisionsstrategi

Kollisionsstrategi, often translated as collision strategy or collision handling, is a fundamental concept in computer science, particularly in the field of data structures. It refers to the methods employed to resolve conflicts that arise when two or more keys or data items attempt to occupy the same location within a data structure, most commonly a hash table. When a hash function maps different keys to the same index or bucket, a collision occurs. Without a proper strategy, this would lead to data loss or incorrect retrieval.

There are two primary categories of collision strategies: open addressing and separate chaining. In open addressing, when a collision happens, the algorithm probes for an alternative, unoccupied slot within the hash table itself. Common probing techniques include linear probing, where the next available slot is checked sequentially; quadratic probing, which uses a quadratic function to determine the next probe location; and double hashing, which employs a secondary hash function to calculate the step size for probing.

Separate chaining, on the other hand, handles collisions by creating a secondary data structure, typically a linked list, at each slot in the hash table. When a collision occurs, the new element is simply added to the linked list associated with that slot. This approach allows multiple elements to be stored at the same index, with retrieval involving traversing the linked list to find the desired element. The choice of collision strategy can significantly impact the performance and efficiency of hash table operations, influencing factors such as insertion time, search time, and memory usage.