20165231 第十周課下補做
阿新 • • 發佈：2018-05-06
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相關知識點
- 創建一個空的鏈表
List<Student> list = new LinkedList<Student>();
- 向鏈表中添加新的結點
list.add(new Student(XXXXXXXXXXXXXXX));
- 刪除結點
list.remove("xxxxxxx");
- 鏈表中數據的插入
list.add("**");
- 鏈表中數據的排序
Collections.sort(); 將list中的元素按升序排序
public static sort(List<E>list)課上習題補做
習題2
代碼：
import java.util.*; class StudentSort implements Comparable { double d=0; String s=""; StudentSort (double d) { this.d=d; } StudentSort (String s) { this.s=s; } public int compareTo(Object b) { StudentSort st=(StudentSort)b; if((this.d-st.d)==0) return -1; else return (int)((this.d-st.d)*1000); } } class Student { String name=null; double math,english,computer,total,aver; Student(String s, double m, double e, double f, double a,double b) { name=s; math=m; english=e; computer=f; total=a; aver=b; } } public class StudentTest { public static void main(String args[]) { TreeMap<StudentSort, Student> treemap = new TreeMap<StudentSort, Student>(); String str[] = {"20165229趙凱傑", "20165230田坤燁", "20165231王楊鴻永", "20165232何彥達", "20165233張雨昕"}; double math[] = {89, 45, 78, 76, 70}; double english[] = {67, 68, 69, 70, 71}; double computer[] = {76, 66, 30, 65, 80}; double total[] = new double[5]; double aver[] = new double[5]; Student student[] = new Student[5]; for (int k = 0; k < student.length; k++) { total[k] = math[k] + english[k] + computer[k]; aver[k] = total[k] / 3; } for (int k = 0; k < student.length; k++) { student[k] = new Student(str[k], math[k], english[k], computer[k], total[k], aver[k]); } StudentSort key[] = new StudentSort[5]; for (int k = 0; k < key.length; k++) { key[k] = new StudentSort(student[k].total); } for (int k = 0; k < student.length; k++) { treemap.put(key[k], student[k]); } int number = treemap.size(); System.out.println("有" + number + "個對象,按總成績排序:"); Collection<Student> collection = treemap.values(); Iterator<Student> iter = collection.iterator(); while (iter.hasNext()) { Student stu = iter.next(); System.out.println("姓名 " + stu.name + " 總成績 " + stu.total); } } }
運行截圖：
代碼碼雲
習題3
代碼：
import java.util.*; public class MyList { public static void main(String [] args) { List<String> list=new LinkedList<String>(); list.add("20165229"); list.add("20165230"); list.add("20165232"); list.add("20165233"); System.out.println("打印初始鏈表"); //把上面四個節點連成一個沒有頭結點的單鏈表 Iterator<String> iter=list.iterator(); while(iter.hasNext()){ String te=iter.next(); System.out.println(te); } //遍歷單鏈表，打印每個結點的 list.add("20165231"); //把你自己插入到合適的位置（學號升序） System.out.println("插入我的學號後排序，打印鏈表"); Collections.sort(list); iter=list.iterator(); while(iter.hasNext()){ String te=iter.next(); System.out.println(te); } //遍歷單鏈表，打印每個結點的 list.remove("20165231"); //從鏈表中刪除自己 System.out.println("刪除我的學號後打印鏈表"); iter=list.iterator(); while(iter.hasNext()){ String te=iter.next(); System.out.println(te); } //遍歷單鏈表，打印每個結點的 } }
運行截圖：
代碼碼雲
第十五章課後編程題
- 第1題：
使用堆棧結構輸出an的若幹項，其中an=2an-1+2an-2，a1=3，a2=8.
import java.util.*; public class E15_1 { public static void main(String[] args) { Stack<Integer> stack=new Stack<Integer>(); stack.push(3); stack.push(8); int k=1; while (k<=10) { for (int i=1;i<=2;i++) { Integer F1=stack.pop(); int f1=F1.intValue(); Integer F2=stack.pop(); int f2=F2.intValue(); Integer temp= new Integer (2 * f1 + 2 * f2); System.out.println(""+temp.toString()); stack.push(temp); stack.push(F2); k++; } } } }
運行截圖：
- 第2題：
將鏈表中的學生英語成績單存放到一個樹集中，使得按成績自動排序，並輸出排序結果
import java.util.*;
class CollegeStu implements Comparable {
int english=0;
String name;
CollegeStu(int english,String name) {
this.name=name;
this.english=english;
}
@Override
public int compareTo(Object b) {
CollegeStu stu=(CollegeStu)b;
return (this.english-stu.english);
}
}
public class E15_2 {
public static void main(String[] args) {
List<CollegeStu> list=new LinkedList<CollegeStu>();
int score []={65, 66, 88, 76, 77};
String name []={"趙凱傑","田坤燁","王楊鴻永","何彥達","張雨昕"};
for (int i=0;i<score.length;i++) {
list.add(new CollegeStu(score[i],name[i]));
}
Iterator<CollegeStu> iter=list.iterator();
TreeSet<CollegeStu> mytree=new TreeSet<CollegeStu>();
while (iter.hasNext()) {
CollegeStu stu=iter.next();
mytree.add(stu);
}
Iterator<CollegeStu> te=mytree.iterator();
while (te.hasNext()) {
CollegeStu stu=te.next();
System.out.println(""+stu.name+" "+stu.english);
}
}
}運行截圖：
- 第3題：
有10個U盤，有兩個重要的屬性：價格和容量，編寫一個應用程序，使用TreeMap
import java.util.*;
class UDiscKey implements Comparable {
double key = 0;
UDiscKey(double d) {
key = d;
}
@Override
public int compareTo(Object b) {
UDiscKey disc = (UDiscKey) b;
if ((this.key - disc.key) == 0) {
return -1;
}
else
{
return (int) ((this.key - disc.key) * 1000);
}
}
}
class UDisc {
int amount;
double price;
UDisc(int m,double e) {
amount=m;
price=e;
}
}
public class E15_3 {
public static void main(String[] args) {
TreeMap<UDiscKey,UDisc> treeMap=new TreeMap<UDiscKey,UDisc>();
int amount[]={1,2,4,8,16};
double price[]={867,266,390,556};
UDisc UDisc[]=new UDisc[4];
for (int k=0;k<UDisc.length;k++) {
UDisc[k]=new UDisc(amount[k],price[k]);
}
UDiscKey key[]=new UDiscKey[4];
for (int k=0;k<key.length;k++) {
key[k]=new UDiscKey(UDisc[k].amount);
}
for (int k=0;k<UDisc.length;k++) {
treeMap.put(key[k],UDisc[k]);
}
int number=treeMap.size();
Collection<UDisc> collection=treeMap.values();
Iterator<UDisc> iter=collection.iterator();
while (iter.hasNext()) {
UDisc disc=iter.next();
System.out.println(""+disc.amount+"G "+disc.price+"元");
}
treeMap.clear();
for (int k=0;k<key.length;k++) {
key[k]=new UDiscKey(UDisc[k].price);
}
for (int k=0;k<UDisc.length;k++) {
treeMap.put(key[k],UDisc[k]);
}
number=treeMap.size();
collection=treeMap.values();
iter=collection.iterator();
while (iter.hasNext()) {
UDisc disc=iter.next();
System.out.println(""+disc.amount+"G "+disc.price+"元");
}
}
}運行截圖：
20165231 第十周課下補做