BSTMap
接口
public interface Map<K,V> {
void add(K key, V value);
V remove(K key);
boolean contains(K key);
V get(K key);
void set(K key,V newValue);
int getSize();
boolean isEmpty();
}
代码实现
public class BSTMap<K extends Comparable<k>,V>implements Map<k,v>{
private class Node{
public K key;
public V value;
public Node left,right;
public Node(K key,V value){
this.key = key;
this.value = value;
right = null;
left = null;
}
}
private Node root ;
private int size;
public BSTMap(){
root = null;
size = 0;
}
@Override
public int getSize(){
return size;
}
@Override
public boolean isEmpty(){
return size == 0;
}
@Override
public void add(K key, V value){
root = add(root,key,value);
}
private Node add(Node node, K key, V value){
if(node == null){
size++;
return new Node(key,value);
}
if(key.compareTo(node.key)==0){
return node;
}else if(key.compareTo(node.key)<0){
return node.left;
}else{
return node.right;
}
}
private Node getNode(Node node,K key){
if(node==null) return null;
if(key.compareTo(node.key)==0){
return node;
}else if(key.compareTo(node.key)<0){
return node.left;
}else{
return node.right;
}
}
@Override
public boolean contains(K key){
return getNode(root,key)!=null;
}
@Override
public V get(K key){
Node node = getNode(root,key);
return node == null?nul:node.value;
}
@Override
public void set(K key, V newValue){
Node node = getNode(root,key);
if(node == null){
throw new IllegalArgumentException(key+ " doesn't exist");
}
node.value = newValue;
}
@Override
public V remove(K key){
Node node = getNode(root,key);
if(Node != null){
root = remove(root,key);
return node.value;
}
return null;
}
private Node remove(Node node, K key) {
if(node == null){
return null;
}
if(key.compateTo(node.key) < 0){
node.left = remove(node.left,key);
return node;
}else if(key.compareTo(node.key) > 0){
node.right = remove(node.right,key);
return node;
}else{
if(node.left == null){
Node rightNode = node.right;
node.right = null;
size--;
return rightNode;
}
if(node.right == null){
Node leftNode = node.left;
node.left = null;
size--;
return leftNode;
}
Node successor = minimun(node.right);
successor.right = removeMin(node.right);
success.left = node.left;
node.right = node.left = null;
return successor;
}
}
private Node minimum(Node node){
if(node.left == null){
return node;
}else{
return minimum(node.left);
}
}
private Node removeMin(Node node){
if(node.left == null){
Node rightNode = node.right;
node.right = null;
size--;
return rightNode;
}
node.left = removeMin(node.left);
return node;
}
}