我正在尝试获取代码以搜索特定年份制作的歌曲
我尝试实现自己的二进制搜索代码，但是它不起作用，而是在我从未要求输入时要求输入
班级：
public class MusicV3
{
// instance variables
private int year;
private String title;
private String artist;
// Constructor for objects of class Music
public MusicV3(String t, int y, String a)
{
// initialize instance variables
title = t;
year = y;
artist = a;
}
public String getTitle()
{
return title;
}
public void setTitle(String t)
{
title = t;
}
public String getArtist()
{
return artist;
}
public void setArtist(String a)
{
artist = a;
}
public int getYear()
{
return year;
}
public void setTitle(int y)
{
year = y;
}
public String toString()
{
String str = String.format( "%-25s %4d %-20s ", title, year , artist);
return str;
}
}
测试器类：
public class MusicV3Tester
{
public static void main(String[]args)
{
int find = 0;
MusicV3[] songs = new MusicV3[10];
MusicV3[] sortedSongs = new MusicV3[songs.length];
songs[0] = new MusicV3("Sugar", 2014, "Maroon 5");
songs[1] = new MusicV3("Mercy", 2016, "Shawn Mendes");
songs[2] = new MusicV3("Shape of You", 2017, "Ed Sheeran");
songs[3] = new MusicV3("Photograph", 2014, "Ed Sheeran");
songs[4] = new MusicV3("Closer", 2016, "The Chainsmokers");
songs[5] = new MusicV3("Galway Girl", 2017, "Ed Sheeran");
songs[6] = new MusicV3("Counting Stars", 2013, "OneRepublic");
songs[7] = new MusicV3("7 Years", 2015, "Lukas Graham");
songs[8] = new MusicV3("Night Changes", 2014, "One Direction");
songs[9] = new MusicV3("What Makes You Beautiful", 2011, "One Direction");
printSongs(songs);
System.out.println();
sortedSongs = sortBySong(songs);
System.out.println("Song list sorted by songs:");
//printSongs(sortedSongs);
System.out.println();
System.out.println("Searching for the song: Paris");
find = findSong(songs, "Paris");
if(find != -1){
System.out.println("We found Paris in the song list: ");
System.out.println(sortedSongs[find]);
}
else
System.out.println("Paris is not in the song list");
System.out.println();
System.out.println("Searching for the song: Sugar");
find = findSong(songs, "Sugar");
if(find != -1){
System.out.println("We found Sugar in the song list: ");
System.out.println(sortedSongs[find]);
}
else
System.out.println("Sugar is not in the song list");
System.out.println();
sortedSongs = sortByYear(songs);
System.out.println("Song list sorted by year:");
//printSongs(sortedSongs);
System.out.println();
System.out.println("Searching for the year: 2000");
find = findYear(songs, 2000);
if(find != -1){
System.out.println("We found songs made in the year 2000 in the song list: ");
System.out.println(sortedSongs[find]);
}
else
System.out.println("Songs made in the year 2000 are not in the song list");
System.out.println();
System.out.println("Searching for the year: 2014");
findYear(songs, 2014);
if(find != -1){
System.out.println("We found songs made in the year 2014 in the song list: ");
System.out.println(sortedSongs[find]);
}
else
System.out.println("Songs made in the year 2014 are not in the song list");
System.out.println();
sortedSongs = sortByArtist(songs);
System.out.println("Song list sorted by artist:");
//printSongs(sortedSongs);
System.out.println();
System.out.println("Searching for the artist: Sia");
findArtist(songs, "Sia");
System.out.println();
System.out.println("Searching for the artist: Ed Sheeran");
findArtist(songs, "Ed Sheeran");
System.out.println();
}
public static void printSongs(MusicV3[] s)
{
System.out.println("Song Year Artist");
System.out.println("-------------------------------------------------------");
for(int i = 0; i < s.length; i++)
System.out.println(s[i]);
}
public static MusicV3[] sortBySong(MusicV3 [] songs){
MusicV3[] sortedList = songs;
int i;
int k;
int posmax;
MusicV3 temp;
for ( i = songs.length - 1 ; i >= 0 ; i-- )
{
posmax = 0;
for ( k = 0 ; k <= i ; k++ )
{
if (songs[k].getTitle().compareTo(songs[posmax].getTitle()) > 0)
posmax = k;
}
temp = songs[i];
songs[i] = songs[posmax];
songs[posmax] = temp;
}
return sortedList;
}
public static MusicV3[] sortByYear(MusicV3 [] movies){
MusicV3[] sortedList = movies;
int i;
int k;
int posmax;
MusicV3 temp;
for ( i = movies.length - 1 ; i >= 0 ; i-- )
{
posmax = 0;
for ( k = 0 ; k <= i ; k++ )
{
if (movies[k].getYear()> movies[posmax].getYear())
posmax = k;
}
temp = movies[i];
movies[i] = movies[posmax];
movies[posmax] = temp;
}
return sortedList;
}
public static MusicV3[] sortByArtist(MusicV3 [] songs){
MusicV3[] sortedList = songs;
int i;
int k;
int posmax;
MusicV3 temp;
for ( i = songs.length - 1 ; i >= 0 ; i-- )
{
posmax = 0;
for ( k = 0 ; k <= i ; k++ )
{
if (songs[k].getArtist().compareTo(songs[posmax].getArtist()) > 0)
posmax = k;
}
temp = songs[i];
songs[i] = songs[posmax];
songs[posmax] = temp;
}
return sortedList;
}
public static int findSong( MusicV3[] songs, String song){
int high = songs.length;
int low = -1;
int probe;
while ( high - low > 1 )
{
probe = ( high + low ) / 2;
if (songs[probe].getTitle().compareTo(song) > 0)
high = probe;
else
low = probe;
}
if ( low >= 0 && songs[low].getTitle().compareTo(song) == 0){
return low;
}
else{
return -1;
}
}
public static int findYear(MusicV3[] songs, int year){
int high = songs.length - 1;
int low = 0;
int probe;
while (low <= high)
{
probe = ( high + low ) / 2;
if (songs[probe].getYear() == year)
return probe;
if(songs[probe].getYear() > year)
low = probe;
else
low = probe + 1;
}
return -1;
}
public static void findArtist(MusicV3[] s, String artist)
{
int found = 0;
for(int i = 0; i < s.length; i++){
if (s[i].getArtist().compareTo(artist) == 0)
{
System.out.println(s[i]);
found++;
}
}
if (found == 0)
{ // we have not found the location
System.out.println("There are no songs on the songs list made in the year " + artist);
System.out.println();
}
else
{
System.out.print("There were " + found + " listings for " + artist);
System.out.println();
}
}
}
忽略歌曲和歌手搜索，我可以做的并且没有问题，但是使用年份搜索，由于它应该正确打印特定年份（2000年和2000年）中的所有歌曲，因此无法正常运行2014年），但并非如此，相反，它根本无法正常工作，并出于某种原因要求提供意见。这是我第一次进行二进制搜索，因此我对此很陌生。
答案 0 :(得分：0)
仅返回其中一个的索引（甚至不返回第一个索引）时，如何显示所有这些索引？
尝试返回结果列表。或索引的Pair<int, int>开始和结束