day 25

Author: cicaleseandrea

src/main/java/com/adventofcode/aoc2024/AoC252024.java

@@ -0,0 +1,70 @@
+package com.adventofcode.aoc2024;
+
+
+import static com.adventofcode.utils.Utils.HASH;
+import static com.adventofcode.utils.Utils.MERRY_CHRISTMAS;
+import static com.adventofcode.utils.Utils.itoa;
+
+import com.adventofcode.Solution;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.stream.Stream;
+
+class AoC252024 implements Solution {
+
+  @Override
+  public String solveFirstPart(final Stream<String> input) {
+    return solve( input, true );
+  }
+
+  @Override
+  public String solveSecondPart(final Stream<String> input) {
+    return solve( input, false );
+  }
+
+  private String solve(final Stream<String> input, final boolean first) {
+    if ( !first ) {
+      return MERRY_CHRISTMAS;
+    }
+    List<int[]> locks = new ArrayList<>();
+    List<int[]> keys = new ArrayList<>();
+    var itr = input.iterator();
+    while ( itr.hasNext() ) {
+      String firstLine = itr.next();
+      if ( firstLine.isEmpty() ) {
+        continue;
+      }
+      if ( firstLine.charAt( 0 ) == HASH ) {
+        locks.add( getPins( itr, false ) );
+      } else {
+        keys.add( getPins( itr, true ) );
+      }
+    }
+    return itoa( keys.stream()
+        .mapToLong( key -> locks.stream().filter( lock -> fits( key, lock ) ).count() )
+        .sum() );
+  }
+
+  private int[] getPins(final Iterator<String> itr, final boolean isKey) {
+    int[] pins = new int[5];
+    for ( int i = 0; i < 6; i++ ) {
+      String line = itr.next();
+      for ( int j = 0; !(isKey && i == 5) && (j < pins.length); j++ ) {
+        if ( line.charAt( j ) == HASH ) {
+          pins[j]++;
+        }
+      }
+    }
+    return pins;
+  }
+
+  private boolean fits(int[] key, int[] lock) {
+    for ( int i = 0; i < lock.length; i++ ) {
+      if ( lock[i] + key[i] > 5 ) {
+        return false;
+      }
+    }
+    return true;
+  }
+}

src/test/java/com/adventofcode/aoc2024/AoC252024Test.java

@@ -0,0 +1,71 @@
+package com.adventofcode.aoc2024;
+
+import static com.adventofcode.AbstractSolutionTest.Type.FIRST;
+import static com.adventofcode.AbstractSolutionTest.Type.SECOND;
+import static com.adventofcode.utils.Utils.MERRY_CHRISTMAS;
+
+import com.adventofcode.AbstractSolutionTest;
+import com.adventofcode.Solution;
+import java.util.List;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameters;
+
+@RunWith(Parameterized.class)
+public class AoC252024Test extends AbstractSolutionTest {
+
+  private static final Solution INSTANCE = new AoC252024();
+
+  public AoC252024Test(final Type type, final String input, final String result) {
+    super( INSTANCE, type, input, result );
+  }
+
+  @Parameters(name = PARAMETERS_MESSAGE)
+  public static Iterable<Object[]> data() {
+    return List.of( new Object[][]{
+        {FIRST, """
+                #####
+                .####
+                .####
+                .####
+                .#.#.
+                .#...
+                .....
+                
+                #####
+                ##.##
+                .#.##
+                ...##
+                ...#.
+                ...#.
+                .....
+                
+                .....
+                #....
+                #....
+                #...#
+                #.#.#
+                #.###
+                #####
+                
+                .....
+                .....
+                #.#..
+                ###..
+                ###.#
+                ###.#
+                #####
+                
+                .....
+                .....
+                .....
+                #....
+                #.#..
+                #.#.#
+                #####
+                """, "3"},
+        {FIRST, getInput( INSTANCE ), "2691"},
+        {SECOND, getInput( INSTANCE ), MERRY_CHRISTMAS}
+    } );
+  }
+}