solved 2024 day 8 part 2

2024/day8/main.py

@@ -11,8 +11,8 @@ y_bound: int = len(data)
 x_bound: int = len(data[0].strip())
 
 for y, line in enumerate(data):
-    for x, char in enumerate(line):
-        if char not in ['.', '\n']:
+    for x, char in enumerate(line.strip()):
+        if char not in ['.']:
             if char not in groups:
                 groups[char] = [Vector(x, y)]
             else:
@@ -22,6 +22,15 @@ for y, line in enumerate(data):
 def in_bounds(v: Vector) -> bool:
     return v.x >= 0 and v.x < x_bound and v.y >= 0 and v.y < y_bound
 
+def print_nodes(antinodes: list[Vector]) -> None:
+    datac = data.copy()
+    for antinode in antinodes:
+        datac[antinode.y] = datac[antinode.y][:antinode.x] + '#' + datac[antinode.y][antinode.x + 1:]
+
+    for line in datac:
+        print(line, end='')
+    print()
+
 antinodes = []
 for char, group in groups.items():
     for i, A in enumerate(group):
@@ -36,13 +45,33 @@ for char, group in groups.items():
             if antinode_pos2 not in antinodes and in_bounds(antinode_pos2):
                 antinodes.append(antinode_pos2)
 
-for antinode in antinodes:
-    data[antinode.y] = data[antinode.y][:antinode.x] + '#' + data[antinode.y][antinode.x + 1:]
+print_nodes(antinodes)
 
-for line in data:
-    print(line, end='')
-
-print(f'\nPart 1: {len(antinodes)}')
+print(f'Part 1: {len(antinodes)}')
 
 # Part 2
+antinodes = []
 
+for char, group in groups.items():
+    for i, A in enumerate(group):
+        for B in group[i + 1:]:
+
+            dist = B - A
+            antinode_pos = A + dist
+            while in_bounds(antinode_pos):
+                if antinode_pos not in antinodes:
+                    antinodes.append(antinode_pos)
+
+                antinode_pos += dist
+
+            dist = dist.inverse()
+            antinode_pos = B + dist
+            while in_bounds(antinode_pos):
+                if antinode_pos not in antinodes:
+                    antinodes.append(antinode_pos)
+
+                antinode_pos += dist
+
+print_nodes(antinodes)
+
+print(f'Part 2: {len(antinodes)}')

2024/day8/test2.text

@@ -0,0 +1,10 @@
+T.........
+...T......
+.T........
+..........
+..........
+..........
+..........
+..........
+..........
+..........

2024/day8/vector.py

@@ -19,6 +19,9 @@ class Vector:
     def abs(self) -> Self:
         return Vector(abs(self.x), abs(self.y))
 
+    def inverse(self) -> Self:
+        return Vector(-self.x, -self.y)
+
     def __str__(self) -> str:
         return f'{self.x}, {self.y}'