GV

GeezerVison

The World Wide Web, restored to 800 pixels of glory.

Home|About|Gaming cabinet|Archives|How it works|Starter sites

On this site

  • Sign in
  • ActionsCI/CD and automation
  • CodespacesCloud development environments
  • All Features
  • Documentation
  • Training
  • Certifications
  • Build with Copilot
  • Customize Copilot
  • Integrations
  • Trending repos
  • GitHub Sponsors
  • Developer articles
  • Enterprises

This view

  • Original page
  • New address

GeezerVison is showing github.com — JavaDataStructures/HashTable/HashTableInterface.java at master · benaich/JavaDataStructures

Expand file tree

/

HashTableInterface.java

Copy path
More file actions
More file actions

Latest commit

 

History

History
History
172 lines (143 loc) · 4.91 KB
/

HashTableInterface.java

Copy path

File metadata and controls

172 lines (143 loc) · 4.91 KB
Raw
Copy raw file
Download raw file
Open symbols panel
Edit and raw actions
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
package HashTable;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.Random;
import java.util.function.Function;
public interface HashTableInterface<K, V> {
public static enum HASH_FUNCTION {
UNIVERSAL, MODULO, MULTIPLICATIF
};
public static final int INITIAL_TABLE_SIZE = 10;
public static final int MAX_TABLE_SIZE = 10000000;
public static final double LOAD_FACTOR = 0.6;
public static final int BIGNUMBER = 9161;
public static final Random r = new Random();
public static final String BLACK_CIRCLE = "\u25CF";
public static final double GOLDEN_RATIO = (1 + Math.sqrt(5)) / 2;
/* get the position of key */
int indexOf(K key);
/* check whether the specified key exist in the hashtable */
boolean contains(K key);
/* update or insert a new item to the hashtable */
void put(K key, V val);
/* get the value of the key*/
V get(K key);
/* remove the specified item */
void delete(K key);
/* remove all data from the hashtable */
void clear();
/* Double the size of the hashtable */
void resize();
/* get the number of elements in the table */
int getSize();
/* get the table size */
int getTableSize();
/* get the number of collisions */
int getNumCollisions();
/* get the number of resizes */
int getNumResizes();
/* get the current load factor */
default float loadFactor() {
return getSize() / (float) getTableSize();
}
/* return de distrubution of the hash table */
public double getDistribution();
/* print the table */
void print();
/* print the table like a "graph" */
void printGraph();
/* print the table curent status */
default void printStatus() {
System.out.println("------------- Table Status -------------------");
System.out.println("Table size : " + getTableSize() + " Actual size : " + getSize());
//System.out.println("Numbre of collisions : " + getNumCollisions());
//System.out.println("Numbre of resises : " + getNumResizes());
System.out.println("Deviation : " + getDistribution());
}
/* return a random universal hashing function */
default Function<K, Integer> getHashingFunction() {
return getHashingFunction(HASH_FUNCTION.UNIVERSAL);
}
/* return a hashing function (modulo, universal or multiplicatif) */
default Function<K, Integer> getHashingFunction(HASH_FUNCTION type) {
Function<K, Integer> f;
if (type == HASH_FUNCTION.MODULO) {
f = x -> Math.abs(x.hashCode()) % getTableSize();
} else if (type == HASH_FUNCTION.UNIVERSAL) {
int a, b, p;
do{
a = r.nextInt();
b = r.nextInt();
}
while (a == 0 || b == 0);
final int r1 = a, r2 = b;
p = nextPrime(BIGNUMBER);
f = x -> Math.abs(((r1 * x.hashCode() + r2) % p) % getTableSize());
} else {
f = x -> {
double c = GOLDEN_RATIO - 1;
double tmp = x.hashCode() * c;
return (int) (((Math.abs(tmp - (int) tmp))) * getTableSize());
};
}
return f;
}
/* get the next prime number after a*/
static int nextPrime(int a) {
while (!isPrime(a)) {
a++;
}
return a;
}
/* check if a number is prime */
static boolean isPrime(int a) {
if (a == 2) {
return true;
} else if (a % 2 == 0) {
return false;
} else {
int i = 3, end = (int) Math.sqrt(a + 0.0);
while (a % i != 0 && i <= end) {
i = i + 2;
}
return i > end;
}
}
/* return a random string (for testing) */
static String randomString() {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < 10; i++) {
char c = (char) (r.nextInt((int) (Character.MAX_VALUE)));
sb.append(c);
}
return sb.toString();
}
static void importFromFile(File file, HashTableInterface<String, String> ht) {
BufferedReader reader;
try {
reader = new BufferedReader(new FileReader(file));
String line;
while ((line = reader.readLine()) != null) {
String[] parts = line.split("\\s");
ht.put(parts[0], parts[1]);
}
reader.close();
} catch (IOException ex) {
System.out.println("file not found");
}
}
static double getStdDeviation(int[] data) {
double sum = 0L;
for (double a : data) {
sum += a;
}
double mean = sum / data.length;
sum = 0L;
for (double a : data) {
sum += (mean - a) * (mean - a);
}
return Math.sqrt(sum / data.length);
}
}
You are visitor 01402503 — GeezerVison does not store the pages you look up.
Best viewed with Netscape Navigator 4.7 or Internet Explorer 6 at 800×600. No cookies required.