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Spotify 'Reversed Binary' test program solved (https://www.spotify.com/us/jobs/tech/reversed-binary/)
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import java.util.Scanner; | |
public class ReversedBinaryNumbers { | |
public static void main(String[] args) { | |
if (args.length == 1) { | |
Scanner scanner=new Scanner(args[0]); | |
if (scanner.hasNextLong()) { | |
long l=scanner.nextLong(); | |
if ((l>0)&&(l<1000000001)) {System.out.println(Long.parseLong(new StringBuilder(Long.toBinaryString(l)).reverse().toString(),2));} | |
} | |
} | |
} | |
} |
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// Recursive solution | |
import java.util.Scanner; | |
public class ReversedBinaryNumbers2 { | |
private static String decimal2BinaryReversed(String s) { | |
if (Long.parseLong(s)<2) {return s;} | |
else {return ((Long.parseLong(s)%2)+decimal2BinaryReversed(String.valueOf(Long.parseLong(s)/2)));} | |
} | |
private static long binary2Decimal(String s) { | |
if (s.length()<2) {return Long.parseLong(s);} | |
else {return (long) ((Long.parseLong(s.substring(0,1))*Math.pow(2,s.length()-1))+binary2Decimal(s.substring(1)));} | |
} | |
public static void main(String[] args) { | |
if (args.length == 1) { | |
Scanner scanner=new Scanner(args[0]); | |
if (scanner.hasNextLong()) { | |
long l=scanner.nextLong(); | |
if ((l>0)&&(l<1000000001)) {System.out.println(binary2Decimal(decimal2BinaryReversed(args[0])));} | |
} | |
} | |
} | |
} |
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