http://www.c-sharpcorner.com/UploadFile/pradeep.tiwari/PradeepTiwariHashtable11072006072247AM/PradeepTiwariHashtable.aspx

The load factor is a measure of how full the hash table is allowed to get before its capacity is automatically increased. When the number of entries in the hash table exceeds the product of the load factor and the current capacity, the hash table is rehashed (that is, internal data structures are rebuilt) so that the hash table has approximately twice the number of buckets. As a general rule, the default load factor (.75) offers a good tradeoff between time and space costs.

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