问题描述
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谁能告诉我RS字符串哈希算法的工作原理或算法?我需要它,但在Google上找不到。请帮助我至少算法,我会自己实现。
解决方法
您是说Robert Sedgewick的字符串哈希算法吗?
uint a = 63689,uint b = 378551
foreach ( byte x ; bytes ) {
value = value * a + x;
a *= b;
}
return value;
(引自http://pallas.telperion.info/d/hash/)。
,Python的实现如下:
def RSHash(key):
a = 63689
b = 378551
hash = 0
for i in range(len(key)):
hash = hash * a + ord(key[i])
a = a * b
return hash
,C ++实现如下:
unsigned int RSHash(const std::string& str)
{
unsigned int b = 378551;
unsigned int a = 63689;
unsigned int hash = 0;
for(std::size_t i = 0; i < str.length(); i++)
{
hash = hash * a + str[i];
a = a * b;
}
return hash;
}
/* End Of RS Hash Function */