algorithm/hello-algo
1
0
Fork 0
mirror of https://github.com/krahets/hello-algo.git synced 2025-11-02 21:24:53 +08:00
Code Issues Packages Projects Releases Wiki Activity

Add Java and C++ code for the section hash algorithm (#560)

Browse Source
This commit is contained in:
Yudong Jin
2023-06-21 19:26:16 +08:00
committed by GitHub
parent 0e2ddba30f
commit 1b1af8d038
6 changed files with 256 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

38
codes/java/chapter_hashing/built_in_hash.java Normal file
View File

@ -0,0 +1,38 @@
/**
* File: built_in_hash.java
* Created Time: 2023-06-21
* Author: Krahets (krahets@163.com)
*/
package chapter_hashing;
import utils.*;
import java.util.*;
public class built_in_hash {
public static void main(String[] args) {
int num = 3;
int hashNum = Integer.hashCode(num);
System.out.println("整数 " + num + " 的哈希值为 " + hashNum);
boolean bol = true;
int hashBol = Boolean.hashCode(bol);
System.out.println("布尔量 " + bol + " 的哈希值为 " + hashBol);
double dec = 3.14159;
int hashDec = Double.hashCode(dec);
System.out.println("小数 " + dec + " 的哈希值为 " + hashDec);
String str = "Hello 算法";
int hashStr = str.hashCode();
System.out.println("字符串 " + str + " 的哈希值为 " + hashStr);
Object[] arr = { 12836, "小哈" };
int hashTup = Arrays.hashCode(arr);
System.out.println("数组 " + Arrays.toString(arr) + " 的哈希值为 " + hashTup);
ListNode obj = new ListNode(0);
int hashObj = obj.hashCode();
System.out.println("节点对象 " + obj + " 的哈希值为 " + hashObj);
}
}

66
codes/java/chapter_hashing/simple_hash.java Normal file
View File

@ -0,0 +1,66 @@
/**
* File: simple_hash.java
* Created Time: 2023-06-21
* Author: Krahets (krahets@163.com)
*/
package chapter_hashing;
public class simple_hash {
/* 加法哈希 */
static int addHash(String key) {
long hash = 0;
final int MODULUS = 1000000007;
for (char c : key.toCharArray()) {
hash = (hash + (int) c) % MODULUS;
}
return (int) hash;
}
/* 乘法哈希 */
static int mulHash(String key) {
long hash = 0;
final int MODULUS = 1000000007;
for (char c : key.toCharArray()) {
hash = (31 * hash + (int) c) % MODULUS;
}
return (int) hash;
}
/* 异或哈希 */
static int xorHash(String key) {
int hash = 0;
final int MODULUS = 1000000007;
for (char c : key.toCharArray()) {
System.out.println((int)c);
hash ^= (int) c;
}
return hash & MODULUS;
}
/* 旋转哈希 */
static int rotHash(String key) {
long hash = 0;
final int MODULUS = 1000000007;
for (char c : key.toCharArray()) {
hash = ((hash << 4) ^ (hash >> 28) ^ (int) c) % MODULUS;
}
return (int) hash;
}
public static void main(String[] args) {
String key = "Hello 算法";
int hash = addHash(key);
System.out.println("加法哈希值为 " + hash);
hash = mulHash(key);
System.out.println("乘法哈希值为 " + hash);
hash = xorHash(key);
System.out.println("异或哈希值为 " + hash);
hash = rotHash(key);
System.out.println("旋转哈希值为 " + hash);
}
}