The load factor is the ratio between the number of stored entries and the number of buckets. A table with 6 entries across 8 buckets sits at 0.75. It is a single number describing how crowded the table is.
As the load factor rises, more keys share buckets, so collisions and chain lengths grow. Lookups that were near constant start scanning longer chains. Implementations watch this number and resize once it crosses a set threshold.
A low load factor wastes memory on empty buckets. A high one wastes time on collisions. Resizing at the threshold keeps the load between those two extremes, so average operations stay near O(1).
Rewriting in plainer words…
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Can a chained table run with a load factor above 1? Can an open-addressed one?Chaining can, since a bucket holds a list. Open addressing has one entry per slot, so it caps at 1 and probing slows well before that.
The load factor is the number of stored entries divided by the number of buckets, so 6 entries in 8 buckets gives 0.75.
It's one number that tells you how crowded the table is.
As it rises, more keys share buckets, so collisions go up, chains get longer, and lookups that were near constant start scanning those chains.
So implementations watch it and resize the table once it crosses a set threshold.
A low load factor wastes memory on empty buckets and a high one wastes time on collisions, so resizing at the threshold keeps average operations near O(1).
Weak answers to avoid
Says how full the table is but gives no formulaToo vague. Give the ratio, entries divided by buckets, and a worked number like 6 entries in 8 buckets being 0.75.
Stops at the definitionThe interviewer wants to know what it controls. Say that a rising load factor lengthens chains and that tables resize at a threshold to keep operations near O(1).
Says a lower load factor is always betterA sparse table wastes memory on empty buckets. Frame it as memory against collision time, with the resize threshold sitting between the two.
Says it can never go above 1That holds only for open addressing. A chained table can store more entries than buckets, so name the collision scheme you mean.
Interview lens
Likely follow-ups, what you can say, and the weak answers to avoid.
