Complete Day 3 Part 2

lib/day3/command.dart

@@ -37,6 +37,7 @@ class Day3Command extends Command {
         .openRead()
         .transform(utf8.decoder)
         .transform(LineSplitter())
+        .asBroadcastStream()
         .map((line) {
           int tens = -1;
           int ones = -1;
@@ -57,5 +58,47 @@ class Day3Command extends Command {
         .reduce((left, right) => left + right);
 
     print("Part 1 Answer: $part1Result");
+
+    var part2Result = await inputFile
+        .openRead()
+        .transform(utf8.decoder)
+        .transform(LineSplitter())
+        .asBroadcastStream()
+        .map((line) {
+          int resultLength = 12;
+          var resultList = List.generate(
+            resultLength,
+            (i) => 0,
+            growable: false,
+          );
+          final chars = line.split("");
+
+          for (final (charIdx, char) in chars.indexed) {
+            final charAsInt = int.parse(char);
+            var charsLeftInStream = chars.length - charIdx - 1;
+            for (final (placeIdx, placeValue) in resultList.indexed) {
+              var placesLeft = resultList.length - placeIdx - 1;
+              if (placesLeft > charsLeftInStream) {
+                continue;
+              }
+              if (charAsInt > placeValue) {
+                resultList[placeIdx] = charAsInt;
+                resultList.fillRange(placeIdx + 1, resultList.length, 0);
+                break;
+              }
+            }
+          }
+
+          int result = 0;
+          for (final placeValue in resultList) {
+            result *= 10;
+            result += placeValue;
+          }
+
+          return result;
+        })
+        .reduce((left, right) => left + right);
+
+    print("Part 2 Answer: $part2Result");
   }
 }