FilesExpand file tree

 master

/

AVLTree.java

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

212 lines (172 loc) · 4.88 KB

 master

/

AVLTree.java

Copy path

Top

File metadata and controls

• Code
• Blame

212 lines (172 loc) · 4.88 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

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

public class AVLTree {

private Node root;

private class Node {

private int key;

private int balance;

private int height;

private Node left, right, parent;

Node(int k, Node p) {

key = k;

parent = p;

}

}

public boolean insert(int key) {

if (root == null)

root = new Node(key, null);

else {

Node n = root;

Node parent;

while (true) {

if (n.key == key)

return false;

parent = n;

boolean goLeft = n.key > key;

n = goLeft ? n.left : n.right;

if (n == null) {

if (goLeft) {

parent.left = new Node(key, parent);

} else {

parent.right = new Node(key, parent);

}

rebalance(parent);

break;

}

}

}

return true;

}

private void delete(Node node){

if(node.left == null && node.right == null){

if(node.parent == null) root = null;

else{

Node parent = node.parent;

if(parent.left == node){

parent.left = null;

}else parent.right = null;

rebalance(parent);

}

return;

}

if(node.left!=null){

Node child = node.left;

while (child.right!=null) child = child.right;

node.key = child.key;

delete(child);

}else{

Node child = node.right;

while (child.left!=null) child = child.left;

node.key = child.key;

delete(child);

}

}

public void delete(int delKey) {

if (root == null)

return;

Node node = root;

Node child = root;

while (child != null) {

node = child;

child = delKey >= node.key ? node.right : node.left;

if (delKey == node.key) {

delete(node);

return;

}

}

}

private void rebalance(Node n) {

setBalance(n);

if (n.balance == -2) {

if (height(n.left.left) >= height(n.left.right))

n = rotateRight(n);

else

n = rotateLeftThenRight(n);

} else if (n.balance == 2) {

if (height(n.right.right) >= height(n.right.left))

n = rotateLeft(n);

else

n = rotateRightThenLeft(n);

}

if (n.parent != null) {

rebalance(n.parent);

} else {

root = n;

}

}

private Node rotateLeft(Node a) {

Node b = a.right;

b.parent = a.parent;

a.right = b.left;

if (a.right != null)

a.right.parent = a;

b.left = a;

a.parent = b;

if (b.parent != null) {

if (b.parent.right == a) {

b.parent.right = b;

} else {

b.parent.left = b;

}

}

setBalance(a, b);

return b;

}

private Node rotateRight(Node a) {

Node b = a.left;

b.parent = a.parent;

a.left = b.right;

if (a.left != null)

a.left.parent = a;

b.right = a;

a.parent = b;

if (b.parent != null) {

if (b.parent.right == a) {

b.parent.right = b;

} else {

b.parent.left = b;

}

}

setBalance(a, b);

return b;

}

private Node rotateLeftThenRight(Node n) {

n.left = rotateLeft(n.left);

return rotateRight(n);

}

private Node rotateRightThenLeft(Node n) {

n.right = rotateRight(n.right);

return rotateLeft(n);

}

private int height(Node n) {

if (n == null)

return -1;

return n.height;

}

private void setBalance(Node... nodes) {

for (Node n : nodes)

reheight(n);

n.balance = height(n.right) - height(n.left);

}

public void printBalance() {

printBalance(root);

}

private void printBalance(Node n) {

if (n != null) {

printBalance(n.left);

System.out.printf("%s ", n.balance);

printBalance(n.right);

}

}

private void reheight(Node node){

if(node!=null){

node.height=1 + Math.max(height(node.left), height(node.right));

}

}

public static void main(String[] args) {

AVLTree tree = new AVLTree();

System.out.println("Inserting values 1 to 10");

for (int i = 1; i < 10; i++)

tree.insert(i);

System.out.print("Printing balance: ");

tree.printBalance();

}

}