You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
hello-algo/codes/cpp/chapter_hashing/simple_hash.cpp

67 lines
1.4 KiB

/**
* File: simple_hash.cpp
* Created Time: 2023-06-21
* Author: krahets (krahets@163.com)
*/
#include "../utils/common.hpp"
/* 加法哈希 */
int addHash(string key) {
long long hash = 0;
const int MODULUS = 1000000007;
for (unsigned char c : key) {
hash = (hash + (int)c) % MODULUS;
}
return (int)hash;
}
/* 乘法哈希 */
int mulHash(string key) {
long long hash = 0;
const int MODULUS = 1000000007;
for (unsigned char c : key) {
hash = (31 * hash + (int)c) % MODULUS;
}
return (int)hash;
}
/* 异或哈希 */
int xorHash(string key) {
int hash = 0;
const int MODULUS = 1000000007;
for (unsigned char c : key) {
hash ^= (int)c;
}
return hash & MODULUS;
}
/* 旋转哈希 */
int rotHash(string key) {
long long hash = 0;
const int MODULUS = 1000000007;
for (unsigned char c : key) {
hash = ((hash << 4) ^ (hash >> 28) ^ (int)c) % MODULUS;
}
return (int)hash;
}
/* Driver Code */
int main() {
string key = "Hello dsad3241241dsa算123法";
int hash = addHash(key);
cout << "加法哈希值为 " << hash << endl;
hash = mulHash(key);
cout << "乘法哈希值为 " << hash << endl;
hash = xorHash(key);
cout << "异或哈希值为 " << hash << endl;
hash = rotHash(key);
cout << "旋转哈希值为 " << hash << endl;
return 0;
}