作者ikari512 ( //StrategyBass)
看板Google
標題Re: [問題] 0rz.net??
時間Mon Jul 24 09:36:51 2006
1F：推 ikari512:現在的問題是如果九億個都被用光是否會override的問題^^" 07/24 01:22
2F：→ ikari512:不是hash的問題喔.. 07/24 01:23
3F：推 cpcmce:你的第一行沒辦法推到第二行的結論吧 07/24 04:19
4F：推 proLIONS:The same string of course will output the same hash 07/24 07:11
5F：→ proLIONS:value. The problem is will two different string map 07/24 07:12
6F：→ proLIONS:to ONE hash value, and it's so called hash collision. 07/24 07:13
我想請教一下
如果說今天是參照別的資訊(例如DB中最久沒用縮址的日期)
而造成的Hash collision還算是Hash collision嗎？
wikipedia的定義是：
In computer science, a hash collision is a situation that occurs when
two distinct inputs into a hash function produce identical outputs.
就是說 明明output不同 但是為了別的理由把他map到之前用過的output
不知道這樣算不算？
抱歉....借用google版討論一下 ><
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7F：推 xanthous2:既然討論hash collision 先搞清楚"hash function"是啥 07/24 11:44
8F：→ xanthous2:如果額外的mapping是對hash output做的 那不是hash問題 07/24 11:49
9F：推 proLIONS:Your thinking is quiet interesting. This extra 07/25 02:12
10F：→ proLIONS:processing may somehow relieve the hash collision 07/25 02:13
11F：→ proLIONS:problem. However, just as what 1st floor says, 07/25 02:13
12F：→ proLIONS:it beyonds the operation of a basic hash function. 07/25 02:13
13F：→ proLIONS:and may take extra computational cost due to 07/25 02:14
14F：→ proLIONS:breaking the regularity of hash functions. 07/25 02:15
15F：→ ikari512:感謝 所以說對hash collision做處理不屬於hash function? 07/25 17:41