一赏壹、用紅黑樹實(shí)現(xiàn)映射
Map類接口
package com.weyan.map;
public interface Map<K, V> {
int size();
boolean isEmpty();
void clear();
V put(K key,V value);
V get(K key);
V remove(K key);
boolean containsKey(K key);
boolean containsValue(V value);
//遍歷
void traversal(Visitor<K, V> visitor);
public static abstract class Visitor<K, V> {
boolean stop;
public abstract boolean visit(K key,V value);
}
}
TreeMap類
package com.weyan.map;
import java.util.Comparator;
import java.util.LinkedList;
import java.util.Queue;
@SuppressWarnings({"unchecked","unused"})
public class TreeMap<K, V> implements Map<K, V> {
private static final boolean RED = false;
private static final boolean BLACK = true;
private int size;
// 根節(jié)點(diǎn)
private Node<K, V> root;
private Comparator<K> comparator;
// java 默認(rèn)構(gòu)造函數(shù)是無參數(shù)
public TreeMap() {
this(null);
}
public TreeMap(Comparator<K> comparator) {
this.comparator = comparator;
}
@Override
public int size() {
return size;
}
@Override
public boolean isEmpty() {
return size == 0;
}
@Override
public void clear() {
root = null;
size = 0;
}
@Override
public V put(K key, V value) {
keyNotNullCheck(key);
// 添加第一個(gè)節(jié)點(diǎn)
if (root == null) {
root = new Node<K, V>(key, value, null);
size++;
// 添加節(jié)點(diǎn)之后的處理
afterPut(root);
return null;
}
// 添加的不是第一個(gè)節(jié)點(diǎn)
// 找到父節(jié)點(diǎn)
Node<K, V> parent = root;
Node<K, V> node = root;
int cmp = 0;
while (node != null) {
parent = node;
cmp = compare(key, node.key);
if (cmp > 0) {
node = node.right;
} else if (cmp < 0) {
node = node.left;
} else {// 相等
V oldValue = node.value;
node.key = key;
node.value = value;
return oldValue;
}
}
// 看看插入到父節(jié)點(diǎn)的哪個(gè)位置
Node<K, V> newNode = new Node<K, V>(key, value, parent);
;
if (cmp > 0) {
parent.right = newNode;
} else if (cmp < 0) {
parent.left = newNode;
}
size++;
// 添加節(jié)點(diǎn)之后的處理
afterPut(newNode);
return null;
}
@Override
public V get(K key) {
Node<K, V> node = node(key);
return node != null ? node.value : null;
}
@Override
public V remove(K key) {
return remove(node(key));
}
@Override
public boolean containsKey(K key) {
return node(key) != null;
}
@Override
public boolean containsValue(V value) {
if(root == null) return false;
Queue<Node<K, V>> queue = new LinkedList<>();
queue.offer(root);
while (!queue.isEmpty()) {
Node<K, V> node = queue.poll();
if (valEquals(value, node.value)) return true;
if(node.left != null) return queue.offer(node.left);
if(node.right != null) return queue.offer(node.right);
}
return false;
}
@Override
public void traversal(Visitor<K, V> visitor) {
if(visitor == null) return;
traversal(root, visitor);
}
private void traversal(Node<K, V> node,Visitor<K, V> visitor) {
if(node == null || visitor.stop) return;
traversal(node.left, visitor);
if(visitor.stop) return;
visitor.visit(node.key, node.value);
traversal(node.right, visitor);
}
private boolean valEquals(V v1,V v2) {
return v1 == null ? v2 == null : v1.equals(v2);
}
// 根據(jù)key查找對應(yīng)的節(jié)點(diǎn)
private Node<K, V> node(K key) {
Node<K, V> node = root;
while (node != null) {
int cmp = compare(key, node.key);
if (cmp == 0) {
return node;
}
if (cmp > 0) {
node = node.right;
} else {
node = node.left;
}
}
return null;
}
private V remove(Node<K, V> node) {
if (node == null) {
return null;
}
size--;
V oldValue = node.value;
// 度為2的節(jié)點(diǎn)
if (node.hasTwoChildrenNode()) {
// 找到后繼節(jié)點(diǎn)
Node<K, V> s = successor(node);
// 用后繼節(jié)點(diǎn)的值覆蓋度為2的節(jié)點(diǎn)的值
node.key = s.key;
node.value = s.value;
// 刪除后繼節(jié)點(diǎn)
node = s;
}
// 刪除node節(jié)點(diǎn)（node的度必然是1或0）
Node<K, V> replacement = node.left != null ? node.left : node.right;
if (replacement != null) {// node是度為1節(jié)點(diǎn)
// 更改parent
replacement.parent = node.parent;
// 更改parent的left/right的指向
if (node.parent == null) {// node是度為1的節(jié)點(diǎn)，并且是根節(jié)點(diǎn)
root = replacement;
} else if (node == node.parent.left) {
node.parent.left = replacement;
} else { // node == node.parent.right
node.parent.right = replacement;
}
// node:刪除的節(jié)點(diǎn)誉裆，刪除之后的處理
afterRemove(node, replacement);
} else if (node.parent == null) {// node是葉子節(jié)點(diǎn)并且是根節(jié)點(diǎn)
root = null;
// node:刪除的節(jié)點(diǎn)觅赊，刪除之后的處理龙助。
afterRemove(node, null);
} else {// node是葉子節(jié)點(diǎn)，但不是根節(jié)點(diǎn)
if (node == node.parent.right) {
node.parent.right = null;
} else {// node == node.parent.left
node.parent.left = null;
}
// node:刪除的節(jié)點(diǎn)渠牲，刪除之后的處理旋炒。
afterRemove(node, null);
}
return oldValue;
}
// 判斷一個(gè)節(jié)點(diǎn)是否為空
private void keyNotNullCheck(K key) {
if (key == null) {
throw new IllegalArgumentException("key must not be null");
}
}
private void afterPut(Node<K, V> node) {
Node<K, V> parent = node.parent;
// 添加的是根節(jié)點(diǎn)
if (parent == null) {
black(node);
return;
}
// 如果父節(jié)點(diǎn)是黑色，直接返回
if (isBlack(parent))
return;
// 叔父節(jié)點(diǎn)
Node<K, V> uncle = parent.sibling();
// 祖父節(jié)點(diǎn)
Node<K, V> grand = parent.parent;
if (isRed(uncle)) {// 叔父節(jié)點(diǎn)是紅色
black(uncle);
black(parent);
// 把祖父節(jié)點(diǎn)當(dāng)做是新添加的節(jié)點(diǎn),染成紅色签杈。
red(grand);
// 遞歸
afterPut(grand);
return;
}
// 叔父節(jié)點(diǎn)不是紅色
if (parent.isLeftChild()) {// L
// grand染成紅色
red(grand);
if (node.isLeftChild()) {// LL
// parent染成黑色
black(parent);
} else {// LR
// node 染成黑色
black(node);
// parent左旋轉(zhuǎn)
rotateLeft(parent);
}
// grand 右旋轉(zhuǎn)
rotateRight(grand);
} else {// R
// grand染成紅色
red(grand);
if (node.isLeftChild()) {// RL
// node 染成黑色
black(node);
// parent右旋轉(zhuǎn)
rotateRight(parent);
} else {// RR
// parent染成黑色
black(parent);
}
// grand 左旋轉(zhuǎn)
rotateLeft(grand);
}
}
// 比較兩個(gè)節(jié)點(diǎn),返回值==0代表e1和e2相等;返回值>0代表e1>e2;返回值<0代表e1<e2
private int compare(K e1, K e2) {
if (comparator != null) {
return comparator.compare(e1, e2);
}
return ((Comparable<K>) e1).compareTo(e2);
}
/* 染色 */
private Node<K, V> color(Node<K, V> node, boolean color) {
if (node == null)
return node;
node.color = color;
return node;
}
// 染紅色
private Node<K, V> red(Node<K, V> node) {
return color(node, RED);
}
// 染紅色
private Node<K, V> black(Node<K, V> node) {
return color(node, BLACK);
}
/* 判斷顏色 */
// 當(dāng)前顏色
private boolean colorOf(Node<K, V> node) {
return node == null ? BLACK : node.color;
}
// 是否為紅色
private boolean isRed(Node<K, V> node) {
return colorOf(node) == RED;
}
// 是否為紅色
private boolean isBlack(Node<K, V> node) {
return colorOf(node) == BLACK;
}
// 左旋轉(zhuǎn)
private void rotateLeft(Node<K, V> grand) {
Node<K, V> parent = grand.right;
Node<K, V> child = parent.left;
grand.right = child;
parent.left = grand;
// 更新parent/grand/child的parent和parent/grand的高度
afterRotate(grand, parent, child);
}
// 右旋轉(zhuǎn)
private void rotateRight(Node<K, V> grand) {
Node<K, V> parent = grand.left;
Node<K, V> child = parent.right;
grand.left = child;
parent.right = grand;
// 更新parent/grand/child的parent和parent/grand的高度
afterRotate(grand, parent, child);
}
// 更新parent/grand/child的parent和parent/grand的高度
private void afterRotate(Node<K, V> grand, Node<K, V> parent, Node<K, V> child) {
// parent稱為子樹的根節(jié)點(diǎn),更新parent的parent
parent.parent = grand.parent;
if (grand.isLeftChild()) {
grand.parent.left = parent;
} else if (grand.isRightChild()) {
grand.parent.right = parent;
} else {
root = parent;
}
// 更新child的parent
if (child != null) {
child.parent = grand;
}
// 更新grand的parent
grand.parent = parent;
}
private void afterRemove(Node<K, V> node, Node<K, V> replacement) {
// 刪除的節(jié)點(diǎn)是紅色
if (isRed(node))
return;
// 用于取代node的子節(jié)點(diǎn)是紅色
if (isRed(replacement)) {
// 將替代的子節(jié)點(diǎn)染為黑色
black(replacement);
return;
}
// 刪除的是根節(jié)點(diǎn)
Node<K, V> parent = node.parent;
if (parent == null)
return;
// 刪除的是黑色葉子節(jié)點(diǎn)[下溢]
// 判斷被刪除的node是左還是右(需要注意)
boolean left = parent.left == null || node.isLeftChild();
Node<K, V> sibling = left ? parent.right : parent.left;
if (left) {// 被刪除的節(jié)點(diǎn)在左邊瘫镇，兄弟節(jié)點(diǎn)在右邊
if (isRed(sibling)) {// 兄弟節(jié)點(diǎn)是紅色
black(sibling);
red(parent);
rotateLeft(parent);
// 更換兄弟
sibling = parent.right;
}
// 兄弟節(jié)點(diǎn)必然是黑色
if (isBlack(sibling.left) && isBlack(sibling.right)) {
// 兄弟節(jié)點(diǎn)沒有一個(gè)紅色子節(jié)點(diǎn),父節(jié)點(diǎn)要向下跟兄弟節(jié)點(diǎn)合并
boolean parentBlack = isBlack(parent);
black(parent);
red(sibling);
if (parentBlack) {
afterRemove(parent, null);
}
} else {// 兄弟節(jié)點(diǎn)至少有一個(gè)紅色子節(jié)點(diǎn)
// 兄弟節(jié)點(diǎn)的右邊是黑色，兄弟要先旋轉(zhuǎn)
if (isBlack(sibling.right)) {
rotateRight(sibling);
sibling = parent.right;
}
color(sibling, colorOf(parent));
black(sibling.right);
black(parent);
rotateLeft(parent);
}
} else {// 被刪除的節(jié)點(diǎn)在右邊答姥，兄弟節(jié)點(diǎn)在左邊
if (isRed(sibling)) {// 兄弟節(jié)點(diǎn)是紅色
black(sibling);
red(sibling);
rotateRight(parent);
// 更換兄弟
sibling = parent.left;
}
// 兄弟節(jié)點(diǎn)必然是黑色
if (isBlack(sibling.left) && isBlack(sibling.right)) {
// 兄弟節(jié)點(diǎn)沒有一個(gè)紅色子節(jié)點(diǎn),父節(jié)點(diǎn)要向下跟兄弟節(jié)點(diǎn)合并
boolean parentBlack = isBlack(parent);
black(parent);
red(sibling);
if (parentBlack) {
afterRemove(parent, null);
}
} else {// 兄弟節(jié)點(diǎn)至少有一個(gè)紅色子節(jié)點(diǎn)
// 兄弟節(jié)點(diǎn)的左邊是黑色铣除，兄弟要先旋轉(zhuǎn)
if (isBlack(sibling.left)) {
rotateLeft(sibling);
sibling = parent.left;
}
color(sibling, colorOf(parent));
black(sibling.left);
black(parent);
rotateRight(parent);
}
}
}
// 前驅(qū)節(jié)點(diǎn)
private Node<K, V> predecessor(Node<K, V> node) {
if (node == null)
return null;
// 前驅(qū)節(jié)點(diǎn)在左子樹當(dāng)中（left.right.right.........）
Node<K, V> p = node.left;
if (p != null) {
while (p.right != null) {
p = p.right;
}
return p;
}
// 從父節(jié)點(diǎn)、祖父節(jié)點(diǎn)當(dāng)中去找前驅(qū)節(jié)點(diǎn)
while (node.parent != null && node == node.parent.right) {
node = node.parent;
}
// node.parent == null && node.left == null
return node.parent;
}
// 后繼節(jié)點(diǎn)
private Node<K, V> successor(Node<K, V> node) {
if (node == null)
return null;
// 前驅(qū)節(jié)點(diǎn)在左子樹當(dāng)中（right.left.left.........）
Node<K, V> p = node.right;
if (p != null) {
while (p.left != null) {
p = p.left;
}
return p;
}
// 從父節(jié)點(diǎn)鹦付、祖父節(jié)點(diǎn)當(dāng)中去找前驅(qū)節(jié)點(diǎn)
while (node.parent != null && node == node.parent.left) {
node = node.parent;
}
// node.parent == null && node.right == null
return node.parent;
}
private static class Node<K, V> {
K key;
V value;
boolean color = RED;
// 左子節(jié)點(diǎn)
Node<K, V> left;
// 右子節(jié)點(diǎn)
Node<K, V> right;
// 父節(jié)點(diǎn)
Node<K, V> parent;
// 構(gòu)造函數(shù)
public Node(K key, V value, Node<K, V> parent) {
this.key = key;
this.value = value;
this.parent = parent;
}
// 是否是葉子節(jié)點(diǎn)
public boolean isLeaf() {
return left == null && right == null;
}
// 度為2節(jié)點(diǎn)
public boolean hasTwoChildrenNode() {
return left != null && right != null;
}
// 當(dāng)前節(jié)點(diǎn)是否是父節(jié)點(diǎn)的左子節(jié)點(diǎn)
public boolean isLeftChild() {
return parent != null && this == parent.left;
}
// 當(dāng)前節(jié)點(diǎn)是否是父節(jié)點(diǎn)的右子節(jié)點(diǎn)
public boolean isRightChild() {
return parent != null && this == parent.right;
}
// 兄弟節(jié)點(diǎn)
public Node<K, V> sibling() {
if (isLeftChild()) {
return parent.right;
}
if (isRightChild()) {
return parent.left;
}
return null;
}
}
}
Main
package com.weyan;
import com.weyan.file.FileInfo;
import com.weyan.file.Files;
import com.weyan.map.Map;
import com.weyan.map.Map.Visitor;
import com.weyan.map.TreeMap;
public class Main {
static void testTreeMap() {
Map<String, Integer> map = new TreeMap<String, Integer>();
map.put("c", 3);
map.put("a", 1);
map.put("b", 2);
map.put("a", 4);
// 遍歷
map.traversal(new Visitor<String, Integer>() {
public boolean visit(String key, Integer value) {
System.out.println(key + "出現(xiàn)的個(gè)數(shù):" + value);
return false;
}
});
}
private static void test2() {
FileInfo fileInfo = Files.read("/Users/xieweiyan/Desktop/weyan/數(shù)據(jù)結(jié)構(gòu)和算法/學(xué)習(xí)代碼/06-二叉搜索樹/src/com/weyan/printer",
new String[] { "java" });
System.out.println("文件數(shù)量：" + fileInfo.getFiles());
System.out.println("代碼行數(shù)：" + fileInfo.getLines());
String[] words = fileInfo.words();
System.out.println("單詞數(shù)量：" + words.length);
Map<String, Integer> map = new TreeMap<String, Integer>();
for (int i = 0; i < words.length; i++) {
// 重復(fù)單詞的個(gè)數(shù)
Integer count = map.get(words[i]);
count = (count == null) ? 1 : (count + 1);
map.put(words[i], count);
}
// 遍歷每一個(gè)單詞
map.traversal(new Visitor<String, Integer>() {
public boolean visit(String key, Integer value) {
System.out.println("key:" + key + "," + "value:" + value);
return false;
}
});
}
public static void main(String[] args) {
testTreeMap();
test2();
}
}
驗(yàn)證結(jié)果
注：
Map的所用key組合在一起尚粘，其實(shí)就是一個(gè)Set
因此，Set可以間接利用Map來內(nèi)部實(shí)現(xiàn)
