Data Update

Task/Amb/Java/amb.java

@@ -0,0 +1,52 @@
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.BiFunction;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public final class AmbTask {
+
+	public static void main(String[] aArgs) {
+		List<List<String>> words = List.of(
+			List.of( "the", "that", "a" ),
+		    List.of( "frog", "elephant", "thing" ),
+		    List.of( "walked", "treaded", "grows" ),
+		    List.of( "slowly", "quickly" ) );		
+
+		System.out.println(Amb(words));		
+	}
+	
+	private static String Amb(List<List<String>> aOptions) {
+		BiFunction<String, String, Boolean> continues = (before, after) -> before.endsWith(after.substring(0, 1));		
+		List<String> ambResult = amb(continues, aOptions, "");
+		return ( ambResult.isEmpty() ) ? "No match found" : String.join(" ", ambResult);		
+	}
+	
+	private static List<String> amb(
+			BiFunction<String, String, Boolean> aBiFunction, List<List<String>> aOptions, String aPrevious) {
+		
+		if ( aOptions.isEmpty() ) {
+			return new ArrayList<String>();
+		}
+
+		for ( String option : aOptions.get(0) ) {
+		    if ( ! aPrevious.isEmpty() && ! aBiFunction.apply(aPrevious, option) ) {
+		    	continue;
+			}
+	
+		    if ( aOptions.size() == 1 ) {
+		    	return Stream.of(option).collect(Collectors.toList());
+		    }
+	
+		    List<String> result = (ArrayList<String>) amb(aBiFunction, aOptions.subList(1, aOptions.size()), option);
+	
+		    if ( ! result.isEmpty() ) {
+				result.add(0, option);
+				return result;
+			}	
+		}
+		
+		return new ArrayList<String>();
+	}
+	
+}