Solved day 10 part 2

Author: Gentleman1983

build.gradle

@@ -4,7 +4,7 @@ plugins {
 
 // project meta data
 group 'de.havox_design.aoc2015'
-version '0.9.4'
+version '0.9.5'
 
 // Switch to gradle "all" distribution.
 wrapper {

day10/src/main/java/de/havox_design/aoc2015/day10/Elves.java

@@ -3,8 +3,6 @@
 import de.havox_design.aoc2015.utils.DataReader;
 
 import java.util.List;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
 
 public class Elves {
     private final String input;
@@ -28,29 +26,30 @@ public int solvePart1() {
     }
 
     public int solvePart2() {
-        return 0;
+        return processForIterations(50).length();
     }
 
     protected String processIteration(String input) {
         StringBuilder newInput = new StringBuilder();
 
         int i = 0;
         while(i < input.length()) {
-            Pattern pattern = Pattern.compile(input.charAt(i) + "+");
-            Matcher matcher = pattern.matcher(input.substring(i));
-
-            if (matcher.find()) {
-                String group = matcher.group(0);
-                i += matcher.group(0).length() - 1;
-                newInput.append(matcher.group(0).length()).append(group.charAt(0));
-            }
-
-            i++;
+            i = lookAndSay(input, newInput, i);
         }
 
         return newInput.toString();
     }
 
+    private int lookAndSay(String input, StringBuilder newInput, int from) {
+        int i = from;
+        while (i < input.length() && input.charAt(i) == input.charAt(from)) {
+            ++i;
+        }
+        newInput.append(i - from);
+        newInput.append(input.charAt(from));
+        return i;
+    }
+
     protected String processForIterations(int iterations) {
         String newInput = input;
 

day10/src/test/java/de/havox_design/aoc2015/day10/Day10Test.java

@@ -24,8 +24,27 @@ void testPart1(String fileName, int expectedResultLength) {
 
     private static Stream<Arguments> getDataForPart1() {
         return Stream.of(
-                Arguments.of("part1sample1.txt", 82350),
-                Arguments.of("part1sample2.txt", 107312)
+                Arguments.of("sample1.txt", 82350),
+                Arguments.of("sample2.txt", 107312),
+                Arguments.of("sample3.txt", 139984),
+                Arguments.of("sample4.txt", 182376),
+                Arguments.of("sample5.txt", 237746)
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("getDataForPart2")
+    void testPart2(String fileName, int expectedResultLength) {
+        Assertions.assertEquals(expectedResultLength, Elves.solvePart2(fileName));
+    }
+
+    private static Stream<Arguments> getDataForPart2() {
+        return Stream.of(
+                Arguments.of("sample1.txt", 1166642),
+                Arguments.of("sample2.txt", 1520986),
+                Arguments.of("sample3.txt", 1982710),
+                Arguments.of("sample4.txt", 2584304),
+                Arguments.of("sample5.txt", 3369156)
         );
     }
 
@@ -38,21 +57,21 @@ void testProcessData(String fileName, String expectedString, int iterations) {
 
     private static Stream<Arguments> getDataForProcessData() {
         return Stream.of(
-                Arguments.of("part1sample1.txt", "11", 1),
-                Arguments.of("part1sample1.txt", "21", 2),
-                Arguments.of("part1sample1.txt", "1211", 3),
-                Arguments.of("part1sample1.txt", "111221", 4),
-                Arguments.of("part1sample1.txt", "312211", 5),
-                Arguments.of("part1sample2.txt", "21", 1),
-                Arguments.of("part1sample2.txt", "1211", 2),
-                Arguments.of("part1sample2.txt", "111221", 3),
-                Arguments.of("part1sample2.txt", "312211", 4),
-                Arguments.of("part1sample3.txt", "1211", 1),
-                Arguments.of("part1sample3.txt", "111221", 2),
-                Arguments.of("part1sample3.txt", "312211", 3),
-                Arguments.of("part1sample4.txt", "111221", 1),
-                Arguments.of("part1sample4.txt", "312211", 2),
-                Arguments.of("part1sample5.txt", "312211", 1)
+                Arguments.of("sample1.txt", "11", 1),
+                Arguments.of("sample1.txt", "21", 2),
+                Arguments.of("sample1.txt", "1211", 3),
+                Arguments.of("sample1.txt", "111221", 4),
+                Arguments.of("sample1.txt", "312211", 5),
+                Arguments.of("sample2.txt", "21", 1),
+                Arguments.of("sample2.txt", "1211", 2),
+                Arguments.of("sample2.txt", "111221", 3),
+                Arguments.of("sample2.txt", "312211", 4),
+                Arguments.of("sample3.txt", "1211", 1),
+                Arguments.of("sample3.txt", "111221", 2),
+                Arguments.of("sample3.txt", "312211", 3),
+                Arguments.of("sample4.txt", "111221", 1),
+                Arguments.of("sample4.txt", "312211", 2),
+                Arguments.of("sample5.txt", "312211", 1)
         );
     }
 }