RosettaCodeData/Task/Rep-string/Java/rep-string-2.java

34 lines
1.1 KiB
Java

import java.util.ArrayList;
import java.util.List;
public final class RepStrings {
public static void main(String[] aArgs) {
List<String> tests = List.of( "1001110011", "1110111011", "0010010010",
"1010101010", "1111111111", "0100101101", "0100100", "101", "11", "00", "1" );
System.out.println("The longest rep-strings are:");
for ( String test : tests ) {
List<String> repeats = repString(test);
String result = repeats.isEmpty() ? "Not a rep-string" : repeats.get(repeats.size() - 1);
System.out.println(String.format("%10s%s%s", test, " -> ", result));
}
}
private static List<String> repString(String aText) {
List<String> repetitions = new ArrayList<String>();
for ( int length = 1; length <= aText.length() / 2; length++ ) {
String possible = aText.substring(0, length);
int quotient = aText.length() / length;
int remainder = aText.length() % length;
String candidate = possible.repeat(quotient) + possible.substring(0, remainder);
if ( candidate.equals(aText) ) {
repetitions.add(possible);
}
}
return repetitions;
}
}