Java program demo 以及一些面试题，笔试题，算法题等等.zip

/** * All rights Reserved, Designed By YuanXiaoShuai * @Title: DataStructure.java * @Package yxs * @Description: TODO(用一句话描述该文件做什么) * @author: 元晓帅 * @date: 2020年4月8日 上午10:20:17 * @version * @Copyright: 2020 yxs. All rights reserved. */ package yxs; import java.util.ArrayList; import java.util.Arrays; import java.util.Comparator; import java.util.Enumeration; import java.util.HashSet; import java.util.Iterator; import java.util.LinkedHashSet; import java.util.LinkedList; import java.util.List; import java.util.ListIterator; import java.util.Random; import java.util.SortedSet; import java.util.TreeSet; import java.util.Vector; /** * @ClassName: DataStructure * @Description:TODO(这里用一句话描述这个类的作用) * @author: 元晓帅 * @date: 2020年4月8日 上午10:20:17 * * @Copyright: 2020 yxs. All rights reserved. */ public class DataStructure implements Comparable<DataStructure> { private int age; private String name; public DataStructure() { super(); } public DataStructure(String name, int age) { super(); this.age = age; this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public String getName() { return name; } public void setName(String name) { this.name = name; } @Override public int compareTo(DataStructure s) { // 此处的this和s前后位置改变会影响排序方式 int num1 = this.age - s.age; int num2 = num1 == 0 ? this.name.compareTo(s.name) : num1; return num2; } public static void main(String[] args) { System.out.println("List:++++++++++++++++++++++++++++++++++++++++++++++++++++++++"); testList(); System.out.println("SortSet:+++++++++++++++++++++++++++++++++++++++++++++++++++++"); testSortSet(); System.out.println("Set:+++++++++++++++++++++++++++++++++++++++++++++++++++++++++"); testSet(); System.out.println("TreeSet:自然排序+++++++++++++++++++++++++++++++++++++++++++++++"); testTreeSet(); System.out.println("TreeSet:比较器排序++++++++++++++++++++++++++++++++++++++++++++++"); testTreeSet2(); } public static void testSet() { HashSet<Integer> set1 = new HashSet<>(); TreeSet<Integer> set2 = new TreeSet<>(); LinkedHashSet<Integer> lSet = new LinkedHashSet<>(); Random r = new Random(); HashSet<Integer> hs = new HashSet<Integer>(); while (hs.size() < 10) { hs.add((r.nextInt(20) + 1)); } for (Integer i : hs) { System.out.println(i); } } public static void testSortSet() { SortedSet<Integer> set = new TreeSet<>(); set.add(0); set.add(3); set.add(2); set.add(6); set.add(3); System.out.println(set); SortedSet<Integer> set2 = new TreeSet<>(); set2.add(5); set.addAll(set2); System.out.println(set); set.remove(set2.first()); System.out.println(set); set.add(5); System.out.println(set); set.removeAll(set2); System.out.println(set); System.out.println(set.contains(9)); System.out.println(set.containsAll(set2)); System.out.println(set.isEmpty()); Iterator<Integer> sIterator = set.iterator(); while (sIterator.hasNext()) { System.out.println(sIterator.next()); } System.out.println(set.size()); set.add(5); System.out.println(set.retainAll(set2)); // 把set2和set的交集给set System.out.println(set); System.out.println(set.toString()); System.out.println(set.retainAll(set)); System.out.println(set.first()); System.out.println(set.last()); System.out.println(set.hashCode()); set.clear(); System.out.println(set); } public static void testTreeSet() { TreeSet<DataStructure> ts = new TreeSet<DataStructure>(); DataStructure s1 = new DataStructure("zfliu", 18); DataStructure s2 = new DataStructure("zfliu", 20); DataStructure s3 = new DataStructure("zfliu", 18); DataStructure s4 = new DataStructure("ZFLIU", 18); DataStructure s5 = new DataStructure("Java", 18); ts.add(s1); ts.add(s2); ts.add(s3); ts.add(s4); ts.add(s5); for (DataStructure s : ts) { System.out.println(s.getName() + s.getAge()); } } public static void testTreeSet2() { TreeSet<DataStructure> ts = new TreeSet<DataStructure>(new Comparator<DataStructure>() { // 匿名内部类实现比较器排序接口 @Override public int compare(DataStructure s1, DataStructure s2) { int num1 = s1.getAge() - s2.getAge(); int num2 = num1 == 0 ? s1.getName().compareTo(s2.getName()) : num1; return num2; } }); DataStructure s1 = new DataStructure("zfliu", 18); DataStructure s2 = new DataStructure("zfliu", 20); DataStructure s3 = new DataStructure("zfliu", 18); DataStructure s4 = new DataStructure("ZFLIU", 18); DataStructure s5 = new DataStructure("Java", 18); ts.add(s1); ts.add(s2); ts.add(s3); ts.add(s4); ts.add(s5); for (DataStructure s : ts) { System.out.println(s.getName() + s.getAge()); } } public static void testList() { List<Integer> l = new ArrayList<Integer>(); ArrayList<Integer> list = new ArrayList<>(); list = (ArrayList<Integer>) l; LinkedList<Integer> list2 = new LinkedList<Integer>(); Vector<Integer> list3 = new Vector<Integer>(); list.add(1); list.add(2); list.add(3); System.out.println(list); System.out.println(list.get(0)); ListIterator<Integer> it = list.listIterator(); // 正向遍历List while (it.hasNext()) { System.out.println(it.next()); } it.add(500000); it.add(500001); // 逆向遍历List // 逆向遍历必须先正向遍历使指针指到后面位置才能使用（使用意义不大） while (it.hasPrevious()) { System.out.println(it.previous()); } list.set(1, 1000); System.out.println(list.get(1)); while (it.hasNext()) { System.out.println(it.next()); } String[] s = new String[] { "A", "B", "C", "D", "E" }; List<String> lista = Arrays.asList(s); System.out.println(lista.get(3)); String[] dest = lista.toArray(new String[0]);// new String[0]是指定返回数组的类型 System.out.println("dest: " + Arrays.toString(dest)); list2.add(2); list2.add(3); System.out.println(list2.getFirst() + " " + list2.getLast()); list2.removeFirst(); list2.removeLast(); System.out.println(list2); list2.add(8888); list2.addFirst(0); list2.addLast(0); System.out.println(list2); list3.add(3); list3.add(4); list3.addElement(99999); System.out.println(list3.elementAt(2)); Iterator<Integer> vIterator = list3.iterator(); // 使用Iterator遍历 Collection // 使用elements Enumeration<Integer> elements = list3.elements(); while (elements.hasMoreElements()) { System.out.println(elements.nextElement()); } } }