Core Concept Mastery • DSA Module
Load factor is how full the table is: (number of elements) / (table size). Keep it below about 0.7. If it gets too high, make a bigger table and rehash everything so that lookups stay fast.
Keep load factor below about 0.7. If the table is 70% full or more, finding an empty slot (probing) or a short chain gets harder.
What is load factor?
Load factor = number of elements in the table / size of the table. So if you have 7 items and the table has 10 slots, load factor = 0.7.
Why it matters
If the table is almost full (e.g. load factor 0.9), finding an empty slot (for probing) or walking a long chain takes longer. So we keep load factor below about 0.7.
What to do when it gets high
Build a bigger table. Then take every key, run the hash function again with the new size, and put each item in its new slot. That is rehashing. After that, the table is less crowded and lookups are fast again.
When the table is too full, collisions go up and probing or long chains make search slow. Resizing and rehashing when load factor is high keeps average performance good.