Day 3

Author: davidaugustat

day3/day3.py

@@ -0,0 +1,116 @@
+symbols = ['!', '§', '$', '%', '&', '/', '{', '}', '(', ')', '[', ']', '=', '?', '*', '+', '~', '#', '-', '_', ',', ';', ':', '\\', '@', '^', '°']
+
+def get_symbol_positions(schematic, symbols_list=symbols):
+ positions = []
+
+ r = len(schematic)
+ c = len(schematic[0])
+ for i in range(r):
+ for j in range(c):
+ if schematic[i][j] in symbols_list:
+ positions.append((i,j))
+ return positions
+
+
+def get_number_positions(schematic):
+ # Structure: (row, col, num_as_string)
+ number_positions = []
+
+ r = len(schematic)
+ c = len(schematic[0])
+ for i in range(r):
+ j = 0
+ while j < c:
+ if schematic[i][j].isdigit():
+ k = 1
+ while(j+k < c and schematic[i][j+k].isdigit()):
+ k += 1
+ num = schematic[i][j:j+k]
+ number_positions.append((i, j, num))
+ j += k-1
+ j += 1
+ return number_positions
+ 
+
+def is_number_part_number(num_pos_info, schematic):
+ i, j, num_string = num_pos_info
+ r = len(schematic)
+ c = len(schematic[0])
+
+ for k in range(j, j + len(num_string)):
+ potential_indices = [(i-1, k), (i+1, k), (i, k-1), (i, k+1), (i-1, k-1), (i-1, k+1), (i+1, k-1), (i+1, k+1)]
+ for pot_i, pot_j in potential_indices:
+ if pot_i < 0 or pot_i >= r or pot_j < 0 or pot_j >= c:
+ continue
+ if schematic[pot_i][pot_j] in symbols:
+ return True
+ return False
+
+
+def is_number_adjacent_to(num_pos_info, star_i, star_j, schematic):
+ i, j, num_string = num_pos_info
+ r = len(schematic)
+ c = len(schematic[0])
+
+ for k in range(j, j + len(num_string)):
+ potential_indices = [(i-1, k), (i+1, k), (i, k-1), (i, k+1), (i-1, k-1), (i-1, k+1), (i+1, k-1), (i+1, k+1)]
+ for pot_i, pot_j in potential_indices:
+ if pot_i < 0 or pot_i >= r or pot_j < 0 or pot_j >= c:
+ continue
+ if pot_i == star_i and pot_j == star_j:
+ return True
+ return False
+
+def get_gear_ratios(schematic):
+ gear_ratios = []
+ star_positions = get_symbol_positions(schematic, ['*'])
+ number_positions = get_number_positions(schematic)
+ for star_i, star_j in star_positions:
+ adjacent_numbers = []
+ for num_pos in number_positions:
+ if is_number_adjacent_to(num_pos, star_i, star_j, schematic):
+ adjacent_numbers.append(int(num_pos[2]))
+ if len(adjacent_numbers) == 2:
+ gear_ratios.append(adjacent_numbers[0] * adjacent_numbers[1])
+ return gear_ratios
+
+
+def get_part_numbers(schematic):
+ all_number_positions = get_number_positions(schematic)
+ part_number_positions = filter(lambda num_pos : is_number_part_number(num_pos, schematic), all_number_positions)
+ part_numbers = list(map(lambda part_number_pos : int(part_number_pos[2]), part_number_positions))
+ return part_numbers
+
+
+def read_data_from_file(filename):
+ schematic = []
+ with open(filename) as file:
+ for line in file:
+ line_string = line.rstrip()
+ schematic.append(line_string)
+ return schematic
+
+
+schematic = read_data_from_file("input.txt")
+# schematic = read_data_from_file("testinput.txt")
+
+# print(schematic)
+# print(schematic[0][3])
+
+# symbol_positions = get_symbol_positions(schematic)
+# print(symbol_positions)
+# number_positions = get_number_positions(schematic)
+# print(number_positions)
+
+# print(is_number_part_number((0, 4, '224'), schematic))
+# print(is_number_part_number((0, 12, '487'), schematic))
+# print(is_number_part_number((1, 89, '439'), schematic))
+# print(is_number_part_number((3, 118, '464'), schematic))
+
+# part_numbers = get_part_numbers(schematic)
+# print(part_numbers)
+# print(f"Sum: {sum(part_numbers)}")
+
+gear_ratios = get_gear_ratios(schematic)
+print(gear_ratios)
+print(f'Sum: {sum(gear_ratios)}')