Java/DataStructures/Lists/CursorLinkedList.java at master · GitPointer/Java · GitHub

History

219 lines (148 loc) · 4.89 KB

Raw

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

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

package DataStructures.Lists;

import java.util.Objects;

public class CursorLinkedList<T> {

private static class Node<T> {

T element;

int next;

Node(T element, int next) {

this.element = element;

this.next = next;

}

boolean isEmpty() {

return element == null;

}

private final int os;

private int head;

private final Node<T>[] cursorSpace;

private int count;

private final static int CURSOR_SPACE_SIZE = 100;

{

// init at loading time

cursorSpace = new Node[CURSOR_SPACE_SIZE];

for (int i = 0; i < CURSOR_SPACE_SIZE; i++) {

cursorSpace[i] = new Node<>(null, i + 1);

}

cursorSpace[CURSOR_SPACE_SIZE - 1].next = 0;

}

public CursorLinkedList() {

os = 0;

count = 0;

head = -1;

}

public void printList() {

if (head != -1) {

int start = head;

while (start != -1) {

T element = cursorSpace[start].element;

System.out.println(element.toString());

start = cursorSpace[start].next;

}

/**

* @return the logical index of the element within the list , not the actual

* index of the [cursorSpace] array

public int indexOf(T element) {

Objects.requireNonNull(element);

Node<T> iterator = cursorSpace[head];

for (int i = 0; i < count; i++) {

if (iterator.element.equals(element)) {

return i;

}

iterator = cursorSpace[iterator.next];

}

return -1;

}

/**

* @param position , the logical index of the element , not the actual one

* within the [cursorSpace] array .

* this method should be used to get the index give by indexOf() method.

* @return

public T get(int position) {

if (position >= 0 && position < count) {

int start = head;

int counter = 0;

while (start != -1) {

T element = cursorSpace[start].element;

if (counter == position) {

return element;

}

start = cursorSpace[start].next;

counter++;

}

return null;

}

public void removeByIndex(int index) {

if (index >= 0 && index < count) {

T element = get(index);

remove(element);

}

public void remove(T element) {

Objects.requireNonNull(element);

// case element is in the head

T temp_element = cursorSpace[head].element;

int temp_next = cursorSpace[head].next;

if (temp_element.equals(element)) {

free(head);

head = temp_next;

} else { // otherwise cases

int prev_index = head;

int current_index = cursorSpace[prev_index].next;

while (current_index != -1) {

T current_element = cursorSpace[current_index].element;

if (current_element.equals(element)) {

cursorSpace[prev_index].next = cursorSpace[current_index].next;

free(current_index);

break;

}

prev_index = current_index;

current_index = cursorSpace[prev_index].next;

}

count--;

}

private void free(int index) {

Node os_node = cursorSpace[os];

int os_next = os_node.next;

cursorSpace[os].next = index;

cursorSpace[index].element = null;

cursorSpace[index].next = os_next;

}

public void append(T element) {

Objects.requireNonNull(element);

int availableIndex = alloc();

cursorSpace[availableIndex].element = element;

if (head == -1) {

head = availableIndex;

}

int iterator = head;

while (cursorSpace[iterator].next != -1) {

iterator = cursorSpace[iterator].next;

}

cursorSpace[iterator].next = availableIndex;

cursorSpace[availableIndex].next = -1;

count++;

}

/**

* @return the index of the next available node

private int alloc() {

//1- get the index at which the os is pointing

int availableNodeIndex = cursorSpace[os].next;

if (availableNodeIndex == 0) {

throw new OutOfMemoryError();

}

//2- make the os point to the next of the @var{availableNodeIndex}

int availableNext = cursorSpace[availableNodeIndex].next;

cursorSpace[os].next = availableNext;

// this to indicate an end of the list , helpful at testing since any err

// would throw an outOfBoundException

cursorSpace[availableNodeIndex].next = -1;

return availableNodeIndex;

}

Java/DataStructures/Lists/CursorLinkedList.java at master · GitPointer/Java · GitHub

Expand file tree

Breadcrumbs

CursorLinkedList.java

Latest commit

History

Breadcrumbs

CursorLinkedList.java

File metadata and controls