一、用链表实现集合
Set类
package com.weyan.set;
public interface Set<E> {
int size();
boolean isEmpty();
void clear();
boolean contains(E element);
void add(E element);
void remove(E element);
//遍历
void traversal(Visitor<E> visitor);
public static abstract class Visitor<E> {
boolean stop;
public abstract boolean visit(E element);
}
}
ListSet类
package com.weyan.set;
import com.weyan.list.LinkedList;
import com.weyan.list.List;
public class ListSet<E> implements Set<E> {
private List<E> list = new LinkedList<>();
@Override
public int size() {
return list.size();
}
@Override
public boolean isEmpty() {
return list.isEmpty();
}
@Override
public void clear() {
list.clear();
}
@Override
public boolean contains(E element) {
return list.contains(element);
}
@Override
//集合的性质：不添加重复的元素
public void add(E element) {
// if (list.contains(element)) return;
// list.add(element);
int index = list.indexOf(element);
if (index != List.ELEMENT_NOT_FOUND) {//存在就覆盖
list.set(index, element);
}else {//不存在就添加
list.add(element);
}
}
@Override
public void remove(E element) {
int index = list.indexOf(element);
if (index != List.ELEMENT_NOT_FOUND) {
list.remove(index);
}
}
@Override
public void traversal(Visitor<E> visitor) {
if (visitor == null) return;
int size = list.size();
for (int i = 0; i < size; i++) {
if (visitor.visit(list.get(i))) return;
}
}
}
二、用红黑树实现集合
TreeSet类
package com.weyan.set;
import com.weyan.tree.RBTree;
public class TreeSet<E> implements Set<E> {
private RBTree<E> tree = new RBTree<>();
@Override
public int size() {
return tree.size();
}
@Override
public boolean isEmpty() {
return tree.isEmpty();
}
@Override
public void clear() {
tree.clear();
}
@Override
public boolean contains(E element) {
return tree.contains(element);
}
@Override
public void add(E element) {
tree.add(element);
}
@Override
public void remove(E element) {
tree.remove(element);
}
@Override
public void traversal(Visitor<E> visitor) {
tree.inorderTraversal();
}
}
用红黑树实现集合(TreeSet)的局限性:
- 红黑树也是二叉搜索树，传入的元素要具备可比较性
三、查找文件当中代码的行树和单词的个数（不包括重复的单词）
工具类：FileInfo
package com.weyan.file;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileFilter;
import java.io.FileReader;
import java.io.IOException;
public class Files {
/**
* 读取文件内容
* @param file
* @return
*/
public static FileInfo read(String file) {
if (file == null) return null;
FileInfo info = new FileInfo();
StringBuilder sb = new StringBuilder();
try (FileReader reader = new FileReader(file);
BufferedReader br = new BufferedReader(reader)) {
String line;
while ((line = br.readLine()) != null) {
sb.append(line).append("\n");
info.setLines(info.getLines() + 1);
}
int len = sb.length();
if (len > 0) {
sb.deleteCharAt(len - 1);
}
} catch (IOException e) {
e.printStackTrace();
}
info.setFiles(info.getFiles() + 1);
info.setContent(sb.toString());
return info;
}
/**
* 读取文件夹下面的文件内容
* @param dir
* @param extensions
* @return
*/
public static FileInfo read(String dir, String[] extensions) {
if (dir == null) return null;
File dirFile = new File(dir);
if (!dirFile.exists()) return null;
FileInfo info = new FileInfo();
dirFile.listFiles(new FileFilter() {
public boolean accept(File subFile) {
String subFilepath = subFile.getAbsolutePath();
if (subFile.isDirectory()) {
info.append(read(subFilepath, extensions));
} else if (extensions != null && extensions.length > 0) {
for (String extension : extensions) {
if (subFilepath.endsWith("." + extension)) {
info.append(read(subFilepath));
break;
}
}
} else {
info.append(read(subFilepath));
}
return false;
}
});
return info;
}
}
工具类：Files
package com.weyan.file;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileFilter;
import java.io.FileReader;
import java.io.IOException;
public class Files {
/**
* 读取文件内容
* @param file
* @return
*/
public static FileInfo read(String file) {
if (file == null) return null;
FileInfo info = new FileInfo();
StringBuilder sb = new StringBuilder();
try (FileReader reader = new FileReader(file);
BufferedReader br = new BufferedReader(reader)) {
String line;
while ((line = br.readLine()) != null) {
sb.append(line).append("\n");
info.setLines(info.getLines() + 1);
}
int len = sb.length();
if (len > 0) {
sb.deleteCharAt(len - 1);
}
} catch (IOException e) {
e.printStackTrace();
}
info.setFiles(info.getFiles() + 1);
info.setContent(sb.toString());
return info;
}
/**
* 读取文件夹下面的文件内容
* @param dir
* @param extensions
* @return
*/
public static FileInfo read(String dir, String[] extensions) {
if (dir == null) return null;
File dirFile = new File(dir);
if (!dirFile.exists()) return null;
FileInfo info = new FileInfo();
dirFile.listFiles(new FileFilter() {
public boolean accept(File subFile) {
String subFilepath = subFile.getAbsolutePath();
if (subFile.isDirectory()) {
info.append(read(subFilepath, extensions));
} else if (extensions != null && extensions.length > 0) {
for (String extension : extensions) {
if (subFilepath.endsWith("." + extension)) {
info.append(read(subFilepath));
break;
}
}
} else {
info.append(read(subFilepath));
}
return false;
}
});
return info;
}
}
验证
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