What is the difference between a linear probing and a quadratic probing in hashing?

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What is the difference between a linear probing and a quadratic probing in hashing?

Linear probing and quadratic probing are two different techniques used in open addressing for resolving collisions in hashing.

Linear probing is a simple method where if a collision occurs, the next available slot in the hash table is checked sequentially until an empty slot is found. The probing sequence is linear, meaning it increments by a fixed amount (usually 1) for each collision. For example, if the initial hash index is i, the next probe will be i+1, then i+2, and so on.

On the other hand, quadratic probing uses a quadratic function to determine the next probe index. If a collision occurs at index i, the next probe index is calculated using a quadratic function such as (i + 1^2), (i + 2^2), (i + 3^2), and so on. This means that the probing sequence increases quadratically, providing a more spread-out distribution of keys in the hash table.

The main difference between linear probing and quadratic probing lies in the probing sequence. Linear probing has a linear probing sequence, while quadratic probing has a quadratic probing sequence. This difference affects the clustering behavior and the efficiency of resolving collisions in the hash table.

In summary, linear probing uses a linear probing sequence, incrementing by a fixed amount for each collision, while quadratic probing uses a quadratic probing sequence, incrementing by a quadratic function for each collision.