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LintCode: Hash Function

更新时间:2022-09-04 23:10:48

C++

(1)模运算(百度百科

  (a±b)%p = (a%p±b%p)%p

  (a*b)%p = (a%p*b%p)%p

  (a^b)%p = ((a%p)^b)%p

(2)使用long型

(3)magic number 33

(4)循环公式

LintCode: Hash Function
class Solution {
public:
    /**
     * @param key: A String you should hash
     * @param HASH_SIZE: An integer
     * @return an integer
     */
    int hashCode(string key, int HASH_SIZE) {
        // write your code here
        int len = key.length();
        int magic = 1;
        long sum = (int)key[0];
        for (int i = 1; i < len; i++) {
            sum = (sum*33)%HASH_SIZE + (int)key[i];
        }
        return (int)sum%HASH_SIZE;
    }
};
LintCode: Hash Function

 

本文转自ZH奶酪博客园博客,原文链接:http://www.cnblogs.com/CheeseZH/p/5105576.html,如需转载请自行联系原作者