solve day 8 part 1

day_08/program.py

@@ -2,14 +2,89 @@
 
 # https://adventofcode.com/2024/day/8
 
+from itertools import combinations
+
+
 def get_lines(filename: str) -> list:
     with open(filename, "r") as file:
         return [line.strip() for line in file.readlines()]
 
 
+def get_antenna_groups(lines: list) -> dict:
+    antenna_groups = {}
+    for row, line in enumerate(lines):
+        for col, char in enumerate(line):
+            if char != ".":
+                if char not in antenna_groups:
+                    antenna_groups[char] = [(row, col)]
+                else:
+                    antenna_groups[char].append((row, col))
+    return antenna_groups
+
+
+def get_anti_nodes(pair: tuple, max_row: int, max_col: int) -> set:
+    anti_nodes = set()
+    a, b = pair
+    a_row, a_col = a
+    b_row, b_col = b
+    vektor_row = b_row - a_row
+    vektor_col = b_col - a_col
+    anti_a_row = a_row - vektor_row
+    anti_a_col = a_col - vektor_col
+    if 0 <= anti_a_row <= max_row and 0 <= anti_a_col <= max_col:
+        anti_nodes.add((anti_a_row, anti_a_col))
+    anti_b_row = b_row + vektor_row
+    anti_b_col = b_col + vektor_col
+    if 0 <= anti_b_row <= max_row and 0 <= anti_b_col <= max_col:
+        anti_nodes.add((anti_b_row, anti_b_col))
+    return anti_nodes
+
+
+def print_field(antennas: list, new_anti_nodes: set, max_row: int, max_col: int) -> None:
+    field = []
+    for i in range(max_row + 1):
+        row = []
+        for j in range(max_col + 1):
+            row.append(".")
+        field.append(row)
+    for antenna in antennas:
+        row, col = antenna
+        field[row][col] = "A"
+    for anti_node in new_anti_nodes:
+        row, col = anti_node
+        if field[row][col] == "A":
+            field[row][col] = "@"
+        else:
+            field[row][col] = "#"
+    for row in field:
+        for char in row:
+            print(char, end="")
+        print()
+    print()
+
+
+def get_all_anti_nodes(antenna_groups: dict, max_row: int, max_col: int) -> set:
+    anti_nodes = set()
+    for antenna_group in antenna_groups:
+        antennas = antenna_groups[antenna_group]
+        antenna_pairs = combinations(antennas, 2)
+        for pair in antenna_pairs:
+            new_anti_nodes = get_anti_nodes(pair, max_row, max_col)
+            anti_nodes.update(new_anti_nodes)
+        # print_field(antennas, anti_nodes, max_row, max_col)
+    return anti_nodes
+
+
 def main():
-    lines = get_lines("sample-input.txt")
-    # lines = get_lines("input.txt")
+    # lines = get_lines("sample-input.txt")
+    # lines = get_lines("sample-input2.txt")
+    lines = get_lines("input.txt")
+
+    antenna_groups = get_antenna_groups(lines)
+    max_row = len(lines) - 1
+    max_col = len(lines[0]) - 1
+    anti_nodes = get_all_anti_nodes(antenna_groups, max_row, max_col)
+    print(f"Part 1: There are {len(anti_nodes)} anti-nodes on the map.")
 
 
 if __name__ == '__main__':

day_08/sample-input2.txt

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