44import java .util .*;
55import java .util .regex .Matcher ;
66import java .util .regex .Pattern ;
7+ import java .util .stream .IntStream ;
78
89public class Day7 extends Day2016 {
910 public Day7 () {
@@ -33,31 +34,14 @@ public boolean supportsTLS() {
3334 }
3435
3536 public boolean supportsSSL () {
36- Set <String > abas = new HashSet <>();
37- for (String supernet : supernets ) {
38- for (int i = 0 ; i < supernet .length () - 2 ; i ++) {
39- if (isABA (supernet , i )) {
40- abas .add (supernet .substring (i , i + 3 ));
41- }
42- }
43- }
44- 45- for (String aba : abas ) {
46- String bab = "" + aba .charAt (1 ) + aba .charAt (0 ) + aba .charAt (1 );
47- if (hypernets .stream ().anyMatch (h -> h .contains (bab ))) {
48- return true ;
49- }
50- }
51- return false ;
37+ return supernets .stream ()
38+ .flatMap (s -> findPatterns (s , 3 , IPv7 ::isABA ))
39+ .map (aba -> new String (new char []{aba .charAt (1 ), aba .charAt (0 ), aba .charAt (1 )}))
40+ .anyMatch (bab -> hypernets .stream ().anyMatch (h -> h .contains (bab )));
5241 }
5342
5443 private static boolean hasABBA (String s ) {
55- for (int i = 0 ; i < s .length () - 3 ; i ++) {
56- if (isABBA (s , i )) {
57- return true ;
58- }
59- }
60- return false ;
44+ return findPatterns (s , 4 , IPv7 ::isABBA ).findAny ().isPresent ();
6145 }
6246
6347 private static boolean isABBA (String s , int i ) {
@@ -70,6 +54,12 @@ private static boolean isABA(String s, int i) {
7054 return s .charAt (i ) == s .charAt (i + 2 ) &&
7155 s .charAt (i ) != s .charAt (i + 1 );
7256 }
57+ 58+ private static java .util .stream .Stream <String > findPatterns (String s , int length , java .util .function .BiPredicate <String , Integer > matcher ) {
59+ return IntStream .range (0 , s .length () - length + 1 )
60+ .filter (i -> matcher .test (s , i ))
61+ .mapToObj (i -> s .substring (i , i + length ));
62+ }
7363 }
7464
7565 @ Override
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