First learned this at Mari, but I still don’t understand. Update: slowly understanding more now.
A hash collision occurs when different input elements map to the same bucket.
Collisions are actually more common than you intuitively think. See the Birthday Paradox 99% chance even around 70 people
Unless you want to make a gazillion buckets, we need to make a hash function to reduce the Hash Collisions.
- Closed Hashing: Use some strategy to find another bucket in the table
- Open Hashing: Each bucket is actually a pointer to short linked list of records