| | Hash table - Wikipedia, the free encyclopedia |
 | | In an ideal hash function, changing any single bit in the key (including extending or shortening the key) would change half the bits of the hash, and this change would be independent of the changes caused by any other bits of the key. |
 | | Hash tables require the design of an effective hash function for each key type, which in many situations is more difficult and time-consuming to design and debug than the mere comparison function required for a self-balancing binary search tree. |
 | | Additionally, in some applications, a fl hat with knowledge of the hash function may be able to supply information to a hash which creates worst-case behavior by causing excessive collisions, resulting in very poor performance (i.e., a denial of service attack). |
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