What song is playing?

Question

Inspired by this xkcd

You work for Shazam and they have a project for you. Some customers are complaining about their app taking up too much space on their phone, so they want you to code a lite version of the app. Unfortunately, your existing code can only understand the word "na", and you have to ship soon. That's okay, we'll do the best with what we've got.

The Challenge

You must write a full program that takes a user input, or takes a command line argument, and print the title and artist of the song. Since we are trying to fix customers complaining about program size, your code must be as short as possible. The input will be a string consisting entirely of na's, with a single space between them. Lowercase/uppercase is arbitrary. This is considered a valid input: Na Na nA na NA This is an invalid input: nah nah NA naNa banana You must determine what song is playing and print it out in exactly this format:

Song: <trackname>
Artist: <artist>

If the input is exactly 8 na's, this matches two separate songs, so you must print both:

Song: Batman Theme
Artist: Neal Hefti

and

Song: Na Na Hey Hey Kiss Him Goodbye
Artist: Steam

If the input is exactly 10 na's, you must print:

Song: Katamari Damacy
Artist: Yuu Miyake

If the input is exactly 11 na's, you must print:

Song: Hey Jude
Artist: The Beatles

If the input is 12 or more na's, you must print

Song: Land Of 1000 Dances
Artist: Wilson Pickett

Lastly, if the input is invalid, there are less than 8 na's, or any of the words are not "na", your program fails to understand the music. So logically, there is only one other song that it could possibly be. You must print:

Song: Africa
Artist: Toto

As usual, standard loopholes apply, and the shortest answer in bytes wins.

Answer 1

Retina, 242

Try it online!

iG`^na( na)*$
iM`na
m`^8$
>Batman Theme,Neal Hefti$n>Na Na Hey Hey Kiss Him Goodbye,Steam
m`^10$
>Katamari Damacy,Yuu Miyake
m`^11$
>Hey Jude,The Beatles
[0-9].+
>Land Of 1000 Dances,Wilson Pickett
m`^[0-9]
>Africa,Toto
>
Song: 
,
$nArtist: 

How it works:

IgnoreCase flag + Grep mode flag + Regex ^na( na)*$. If the input is valid, print it as is. If not, print nothing.

iG`^na( na)*$

IgnoreCase flag + Match mode flag + Regex na. Count the "na"s and print the number.

iM`na

If the string is exactly "8", replace by the second line.

m`^8$
>Batman Theme,Neal Hefti$n>Na Na Hey Hey Kiss Him Goodbye,Steam

If the string is exactly "10", replace by the second line.

m`^10$
>Katamari Damacy,Yuu Miyake

If the string is exactly "11", replace by the second line.

m`^11$
>Hey Jude,The Beatles

If the string matches [0-9].+, replace by the second line. This is neither true for single digit numbers, 10 and 11 as they already have been repaced nor any of the above replacement strings.

[0-9].+
>Land Of 1000 Dances,Wilson Pickett

If none of the above matched, the string still starts with a number. Default to Toto, Africa.

m`^[0-9]
>Africa,Toto

Replace the placeholders > and , by Song: and Artist:.

>
Song: 
,
$nArtist: 

Answer 2

JavaScript (ES6), 276 bytes

alert(`Song: `+([,`Batman Theme,Neal Hefti
Song: Na Na Hey Hey Kiss Him Goodbye,Steam`,,`Katamari Damacy,Yuu Miyake`,`Hey Jude,The Beatles`,`Land Of 1000 Dances,Wilson Pickett`][+prompt(i=0).replace(/na( |$)/gi,_=>++i)&&(i>11?4:i-7)]||`Africa,Toto`).replace(/,/g,`
Artist: `))

Explanation

Input can optionally contain one trailing space.

alert(                 // output the result
  `Song: `+([          // insert the "Song:" label
      ,                // set the first element to undefined in case input is empty

      // Songs
      `Batman Theme,Neal Hefti
Song: Na Na Hey Hey Kiss Him Goodbye,Steam`,
      ,
      `Katamari Damacy,Yuu Miyake`,
      `Hey Jude,The Beatles`,
      `Land Of 1000 Dances,Wilson Pickett`

    ][
      +                // if the input string was made up only of "na"s, the replace would
                       //     return a string containing only digits, making this return a
                       //     number (true), but if not, this would return NaN (false)
        prompt(        // get the input string
          i=0          // i = number of "na"s in input string
        ).replace(     // replace each "na" with a number
          /na( |$)/gi, // find each "na"
          _=>++i       // keep count of the "na"s and replace with a (non-zero) number
        )
      &&(i>11?4:i-7)   // select the song based on the number of "na"s
    ]
      ||`Africa,Toto`  // default to Africa
  ).replace(/,/g,`
Artist: `)             // insert the "Artist:" label
)

Test

var prompt = () => input.value;
var alert = (text) => result.textContent = text;
var solution = () => {

alert(`Song: `+([,`Batman Theme,Neal Hefti
Song: Na Na Hey Hey Kiss Him Goodbye,Steam`,,`Katamari Damacy,Yuu Miyake`,`Hey Jude,The Beatles`,`Land Of 1000 Dances,Wilson Pickett`][+prompt(i=0).replace(/na( |$)/gi,_=>++i)&&(i>11?4:i-7)]||`Africa,Toto`).replace(/,/g,`
Artist: `))

}

<input type="text" id="input" value="na na Na na NA na na nA" />
<button onclick="solution()">Go</button>
<pre id="result"></pre>

Answer 3

PowerShell, 278 bytes

• Can handle any amount of whitespace
• No regex whatsoever!
• Implicit typecasting FTW!

@{8='Batman Theme/Neal Hefti','Na Na Hey Hey Kiss Him Goodbye/Steam'
10='Katamari Damacy/Yuu Miyake'
11='Hey Jude/The Beatles'
12='Land Of 1000 Dances/Wilson Pickett'}[[math]::Min($args.Count*!($args|?{$_-ne'na'}),12)]|%{'Song: {0}
Artist: {1}'-f($_+'Africa/Toto'*!$_-split'/')}

Ungolfed

@{8='Batman Theme/Neal Hefti','Na Na Hey Hey Kiss Him Goodbye/Steam' # array
10='Katamari Damacy/Yuu Miyake'
11='Hey Jude/The Beatles'
12='Land Of 1000 Dances/Wilson Pickett'} # Hashtable of songs
[   # Get value by key from hashtable
    # If key is invalid, silently return null value

    [math]::Min( # Clamp max value to 12
        $args.Count* # Multiply count of argumens
                     # true/false will be cast to 1/0
            ! # Negate result of expression
              # Will cast empty array to 'false'
              # and non-empty array to 'true'
            (
                # Return non-empty array if input arguments
                # contain anything other than 'na'
                $args | Where-Object {$_ -ne 'na'} 
            ),
        12
    )
] | ForEach-Object { # Send value from hashtable down the pipeline,
                     # This allows to process arrays in hasthable values
    'Song: {0}
    Artist: {1}' -f ( # Format string
        $_+ # Add to current pipeline variable
            'Africa/Toto'*!$_ # If pipeline variable is empty,
                              # then add default song to it
                              # Example: 'Test'*1 = 'Test'
                              #          'Test'*0 = null
        -split '/' # Split string to array for Format operator
    )
}

Usage

PS > .\WhatSong.ps1 na na na na na na na na
Song: Batman Theme
Artist: Neal Hefti
Song: Na Na Hey Hey Kiss Him Goodbye
Artist: Steam

PS > .\WhatSong.ps1 Na na na na na na na na na Na
Song: Katamari Damacy
Artist: Yuu Miyake

PS > .\WhatSong.ps1 Na na na na na na na na na BanaNa
Song: Africa
Artist: Toto

Answer 4

C (gcc), 403 395 370 365 bytes

-8 -5 bytes thanks to ceilingcat

Pretty much as straight-forward as can be.

f(char*s){int*a[]={"Neal Hefti","Steam","Yuu Miyake","The Beatles","Wilson Pickett","Toto","Batman Theme","Na Na Hey Hey Kiss Him Goodbye","Katamari Damacy","Hey Jude","Land Of 1000 Dances","Africa"},i=1,l=0,j=1;for(;*s;s+=s[2]?3:2)i=(*s|32)^'n'|(s[1]|32)^97|s[2]>32,l++;for(i=i?5:l^8?l^10?l^11?l>11?4:5:3:2:j++;j--;)printf("Song: %s\nArtist: %s\n",a[6+i--],a[i]);}

Try it online!

Answer 5

Rust, 501 477 bytes

fn main(){let(mut i,mut n)=(String::new(),0);let(s,a);std::io::stdin().read_line(&mut i);i=i.trim().to_lowercase();let o=i.split(" ");for w in o{if w!="na"{n=0;break}else{n+=1}}match n{8=>{println!("Song: Batman Theme\nArtist: Neal Hefti");s="Na Na Hey Hey Kiss Him Goodbye";a="Steam"}10=>{s="Katamari Damacy";a="Yuu Miyake"}11=>{s="Hey Jude";a="The Beatles"}_=>{if n>=12{s="Land Of 1000 Dances";a="Wilson Pickett"}else{s="Africa";a="Toto"}}}print!("Song: {}\nArtist: {}",s,a)}

Ungolfed

fn main() {
    let (mut input_string, mut na_counter) = (String::new(), 0);
    let (song_name, artist_name);

    std::io::stdin().read_line(&mut input_string);
    input_string = input_string.trim().to_lowercase();
    let output = input_string.split(" ");

    for word in output {
        if word != "na" {
            na_counter = 0;
            break;
        } else {
            na_counter += 1;
        }
    }

    match na_counter {
        8 => {
            println!("Song: Batman Theme\nArtist: Neal Hefti");
            song_name = "Na Na Hey Hey Kiss Him Goodbye";
            artist_name = "Steam";
        }
        10 => {
            song_name = "Katamari Damacy";
            artist_name = "Yuu Miyake";
        }
        11 => {
            song_name = "Hey Jude";
            artist_name = "The Beatles";
        }
        _ => {
            if na_counter >= 12 {
                song_name = "Land Of 1000 Dances";
                artist_name = "Wilson Pickett";
            } else {
                song_name = "Africa";
                artist_name = "Toto";
            }
        }
    }

    print!("Song: {}\nArtist: {}", song_name, artist_name);
}

Edit: removed an unnecessary to_string and type annotations

Answer 6

Perl 5, 312 292 bytes

$_=lc<>;$n="(na ?)";/^(na ){7}na$|(na ){9,}na/ or$_="%Africa&Toto";s/$n{12,}/%Land Of 1000 Dances&Wilson Pickett/;s/$n{11}/%Hey Jude&The Beatles/;s/$n{10}/%Katamari Damacy&Yuu Miyake/;s/$n{8}/%Batman Theme&Neal Hefti\n%Na Na Hey Hey Kiss Him Goodbye&Steam/;s/&/\nArtist: /g;s/%/Song: /g;print

Try it online!

Ungolfed:

$_ = lc <STDIN>;
$_ =~ /^(na ){7}na$|(na ){9,}na/ or $_ = "%Africa&Toto";
$_ =~ s/(na ?){12,}/%Land Of 1000 Dances&Wilson Pickett/;
$_ =~ s/(na ?){11}/%Hey Jude&The Beatles/;
$_ =~ s/(na ?){10}/%Katamari Damacy&Yuu Miyake/;
$_ =~ s/(na ?){8}/%Batman Theme&Neal Hefti\n%Na Na Hey Hey Kiss Him Goodbye&Steam/;
$_ =~ s/&/\nArtist: /g;
$_ =~ s/%/Song: /g;
print $_

Answer 7

Perl 5 -pa, 248 bytes

$_=/^(na ?)+$/&&(@F==8?",Batman Theme;Neal Hefti,Na Na Hey Hey Kiss Him Goodbye;Steam":@F==10?"Katamari Damacy;Yuu Miyake":@F==11?",Hey Jude;The Beatles":@F>11?",Land Of 1000 Dances;Wilson Pickett":0)||",Africa;Toto";s/;/
Artist: /gm;s/,/
Song: /gm

Try it online!

Answer 8

Python 453 440 406 380 bytes

EDIT: Thanks to Cyoce for reducing 13 bytes!

EDIT: Thanks again to Cyoce!

EDIT: Thanks to RainerP. for helping me imrpove the algorithm on certain invalid cases.

This is a rough draft of a Python program. I believe it can be definitely golfed, maybe to 300-400 bytes. But will work on that soon.

f=0
S='Song:'
A='\nArtist:'
l="Batman Theme,Neal Hefti,Na Na Hey Kiss Him Goodbye,Steam,Katamari Damacy,Yuu Miyake,Hey Jude,Beatles,Land of the 1000 Dances,Wilson Pickett,Africa,Toto".split(',')
s=raw_input().lower()+" "
n=s.count("na ")
n*=n*3==len(s)
if n>11:f=8
if n==10:f=4
if n==11:f=6
if n<8or n==9:f=10
if f:print S+l[f]+A+l[f+1]
else:print S+l[0]+A+l[1]+"\n"+S+l[2]+A+l[3]

Try here!

Answer 9

sh + coreutils, 290

Albeit longer than my other submission, this one is straightforward and pretty much ungolfed, so i included it anyway.

grep -Ei "^na( na)*$"|wc -w|awk '{s="Song: ";a="\nArtist: ";p=s"Africa"a"Toto"}$1==8{p=s"Batman Theme"a"Neal Hefti\n"s"Na Na Hey Hey Kiss Him Goodbye"a"Steam"}$1>9{p=s"Katamari Damacy"a"Yuu Miyake"}$1>10{p=s"Hey Jude"a"The Beatles"}$1>11{p=s"Land Of 1000 Dances"a"Wilson Pickett"}{print p}'

How it works:

If the input is valid, print it as is. If not, print nothing.

grep -Ei "^na( na)*$"

Count the words.

wc -w

Simple look up table, Song: and Artist: are kept in variables.

awk '
    {s="Song: ";a="\nArtist: ";p=s"Africa"a"Toto"}
    $1==8{p=s"Batman Theme"a"Neal Hefti\n"s"Na Na Hey Hey Kiss Him Goodbye"a"Steam"}
    $1>9{p=s"Katamari Damacy"a"Yuu Miyake"}
    $1>10{p=s"Hey Jude"a"The Beatles"}
    $1>11{p=s"Land Of 1000 Dances"a"Wilson Pickett"}
    {print p}
'

Answer 10

Julia, 325 bytes

Probably could be golfed further.

p(s,a)=println("Song: $s\nArtist: $a");ismatch(r"^(na )*na$",ARGS[1])&&(c=length(split(ARGS[1],"na"))-1)==8?(p("Batman Theme","Neal Hefti"),p("Na Na Hey Hey Kiss Him Goodbye","Steam")):c==10?p("Katamari Damacy","Yuu Miyake"):c==11?p("Hey Jude","The Beatles"):c>=12?p("Land Of 1000 Dances","Wilson Pickett"):p("Africa","Toto")

Answer 11

Java 8, 353 bytes

s->{int n=s.split(" ").length,b=s.matches("(na ?)+")?1:0;s="Africa";return"Song: "+(b>0?n<8?s:n<9?"Batman Theme\nArtist: Neal Hefti\nSong: Na Na Hey Hey Kiss Him Goodbye":n>11?"Land of 1000 Dances":n>10?"Hey Jude":n>9?"Katamari Damacy":"":s)+"\nArtist: "+(b>0?n<8?"Toto":n<9?"Steam":n>11?"Wilson Pickett":n>10?"The Beatles":n>9?"Yuu Miyake":"":"Toto");}

Explanation:

Try it online.

s->{                             // Method with String as both parameter and return-type
  int n=s.split(" ").length,     //  The amount of words when split by spaces
      b=s.matches("(na ?)+")?1:0;//  Whether the input matches the regex "^(na ?)+$"
  s="Africa";                    //  Set the input we no longer need to "Africa"
  return"Song: "                 //  Return "Song: "
    +(b>0?                       //   +If the input matched the regex:
       n<8?                      //     If there are less than 8 "na"'s: 
        s                        //      Append "Africa"
       :n<9?                     //     Else-if there are exactly 8 "na"'s:
        "Batman Theme\nArtist: Neal Hefti\nSong: Na Na Hey Hey Kiss Him Goodbye"
                                 //      Append the String above
       :n>11?                    //     Else-if there are 12 or more "na"'s:
        "Land of 1000 Dances"    //      Append "Land of 1000 Dances"
       :n>10?                    //     Else-if there are exactly 11 "na"'s:
        "Hey Jude"               //      Append "Hey Jude"
       :n>9?                     //     Else-if there are exactly 10 "na"'s:
        "Katamari Damacy"        //      Append "Katamari Damacy"
       :                         //     Else (there are exactly 9 "na"'s):
        ""                       //      Append nothing
      :                          //    Else:
       s)                        //     Append "Africa"
    +"\nArtist: "                //   +Append a new-line and "Artist: "
    +(b>0?                       //   +If the input matched the regex:
       n<8?                      //     If there are less than 8 "na"'s:
        "Toto"                   //      Append "Toto"
       :n<9?                     //     Else-if there are exactly 8 "na"'s:
        "Steam"                  //      Append "Steam"
       :n>11?                    //     Else-if there are 12 or more "na"'s:
        "Wilson Pickett"         //      Append "Wilson Pickett"
       :n>10?                    //     Else-if there are exactly 11 "na"'s:
        "The Beatles"            //      Append "The Beatles"
       :n>9?                     //     Else-if there are exactly 10 "na"'s:
        "Yuu Miyake"             //      Append "Yuu Miyake"
       :                         //     Else (there are exactly 9 "na"'s):
        ""                       //      Append nothing
      :                          //    Else:
       "Toto");}                 //     Append "Toto"