Java/DataStructures/Lists/SinglyLinkedList.java at master · java66liu/Java · GitHub

History

300 lines (263 loc) · 7.11 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

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

package DataStructures.Lists;

/**

* This class implements a SinglyLinked List. This is done

* using SinglyLinkedList class and a LinkForLinkedList Class.

* <p>

* A linked list is similar to an array, it hold values.

* However, links in a linked list do not have indexes. With

* a linked list you do not need to predetermine it's size as

* it grows and shrinks as it is edited. This is an example of

* a singly linked list. Elements can only be added/removed

* at the head/front of the list.

public class SinglyLinkedList {

/**

* Head refer to the front of the list

private Node head;

/**

* size of SinglyLinkedList

private int size;

/**

* init SinglyLinkedList

public SinglyLinkedList() {

head = new Node(0);

size = 0;

}

/**

* Init SinglyLinkedList with specified head node and size

* @param head the head node of list

* @param size the size of list

public SinglyLinkedList(Node head, int size) {

this.head = head;

this.size = size;

}

/**

* This method inserts an element at the head

* @param x Element to be added

public void insertHead(int x) {

insertNth(x, 0);

}

/**

* insert an element at the tail of list

* @param data Element to be added

public void insert(int data) {

insertNth(data, size);

}

/**

* Inserts a new node at a specified position

* @param data data to be stored in a new node

* @param position position at which a new node is to be inserted

public void insertNth(int data, int position) {

checkBounds(position, 0, size);

Node cur = head;

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

cur = cur.next;

}

Node node = new Node(data);

node.next = cur.next;

cur.next = node;

size++;

}

/**

* Insert element to list, always sorted

* @param data to be inserted

public void insertSorted(int data) {

Node cur = head;

while (cur.next != null && data > cur.next.value) {

cur = cur.next;

}

Node newNode = new Node(data);

newNode.next = cur.next;

cur.next = newNode;

size++;

}

/**

* This method deletes an element at the head

* @return The element deleted

public void deleteHead() {

deleteNth(0);

}

/**

* This method deletes an element at the tail

public void delete() {

deleteNth(size - 1);

}

/**

* This method deletes an element at Nth position

public void deleteNth(int position) {

checkBounds(position, 0, size - 1);

Node cur = head;

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

cur = cur.next;

}

//Node destroy = cur.next;

cur.next = cur.next.next;

//destroy = null; // clear to let GC do its work

size--;

}

/**

* @param position to check position

* @param low low index

* @param high high index

* @throws IndexOutOfBoundsException if {@code position} not in range {@code low} to {@code high}

public void checkBounds(int position, int low, int high) {

if (position > high || position < low) {

throw new IndexOutOfBoundsException(position + "");

}

/**

* clear all nodes in list

public void clear() {

if (size == 0) {

return;

}

Node prev = head.next;

Node cur = prev.next;

while (cur != null) {

prev = null; // clear to let GC do its work

prev = cur;

cur = cur.next;

}

prev = null;

head.next = null;

size = 0;

}

/**

* Checks if the list is empty

* @return true is list is empty

public boolean isEmpty() {

return size == 0;

}

/**

* Returns the size of the linked list

public int size() {

return size;

}

@Override

public String toString() {

if (size == 0) {

return "";

}

StringBuilder builder = new StringBuilder();

Node cur = head.next;

while (cur != null) {

builder.append(cur.value).append("->");

cur = cur.next;

}

return builder.replace(builder.length() - 2, builder.length(), "").toString();

}

/**

* Merge two sorted SingleLinkedList

* @param listA the first sorted list

* @param listB the second sored list

* @return merged sorted list

public static SinglyLinkedList merge(SinglyLinkedList listA, SinglyLinkedList listB) {

Node headA = listA.head.next;

Node headB = listB.head.next;

int size = listA.size() + listB.size();

Node head = new Node();

Node tail = head;

while (headA != null && headB != null) {

if (headA.value <= headB.value) {

tail.next = headA;

headA = headA.next;

} else {

tail.next = headB;

headB = headB.next;

}

tail = tail.next;

}

if (headA == null) {

tail.next = headB;

}

if (headB == null) {

tail.next = headA;

}

return new SinglyLinkedList(head, size);

}

/**

* Main method

* @param args Command line arguments

public static void main(String args[]) {

SinglyLinkedList myList = new SinglyLinkedList();

assert myList.isEmpty();

assert myList.toString().equals("");

myList.insertHead(5);

myList.insertHead(7);

myList.insertHead(10);

assert myList.toString().equals("10->7->5");

myList.deleteHead();

assert myList.toString().equals("7->5");

myList.insertNth(11, 2);

assert myList.toString().equals("7->5->11");

myList.deleteNth(1);

assert myList.toString().equals("7->11");

myList.clear();

assert myList.isEmpty();

/* Test MergeTwoSortedLinkedList */

SinglyLinkedList listA = new SinglyLinkedList();

SinglyLinkedList listB = new SinglyLinkedList();

for (int i = 10; i >= 2; i -= 2) {

listA.insertSorted(i);

listB.insertSorted(i - 1);

}

assert listA.toString().equals("2->4->6->8->10");

assert listB.toString().equals("1->3->5->7->9");

assert SinglyLinkedList.merge(listA, listB).toString().equals("1->2->3->4->5->6->7->8->9->10");

}

/**

* This class is the nodes of the SinglyLinked List.

* They consist of a value and a pointer to the node

* after them.

class Node {

/**

* The value of the node

int value;

/**

* Point to the next node

Node next;

Node() {

}

/**

* Constructor

* @param value Value to be put in the node

Node(int value) {

this(value, null);

}

Node(int value, Node next) {

this.value = value;

this.next = next;

}

Java/DataStructures/Lists/SinglyLinkedList.java at master · java66liu/Java · GitHub

Expand file tree

Breadcrumbs

SinglyLinkedList.java

Latest commit

History

Breadcrumbs

SinglyLinkedList.java

File metadata and controls