127 lines
3.8 KiB
Python
127 lines
3.8 KiB
Python
import sys
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sys.path.append('../lib')
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import tools, re
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class Scheme(object):
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def __init__(self, inp):
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self.grid = []
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self.grid.append(['.' for _ in range(len(inp[0])+2)])
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for line in inp:
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self.grid.append(['.'] + list(line) + ['.'])
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self.grid.append(['.' for _ in range(len(inp[0])+2)])
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self.part_numbers = []
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self.gears = []
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def __str__(self):
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out = ''
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for row in self.grid:
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out += ''.join(row) + '\n'
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return out
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def _isdigit(self, y, x) -> bool:
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return self.grid[y][x].isdigit()
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def _issymbol(self, y, x) -> bool:
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return (not self._isdigit(y, x)) and (self.grid[y][x] != '.')
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def _find_all_symbols(self) -> list:
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all_symbols = []
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for y in range(len(self.grid)):
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for x in range(len(self.grid[y])):
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if self._issymbol(y, x):
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all_symbols.append((y, x))
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return all_symbols
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def _find_adjacent_numerals(self, y, x) -> list:
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tmp = dict()
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for yadd in [-1, 0, 1]:
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for xadd in [-1, 0, 1]:
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x_, y_ = y + yadd, x + xadd
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if self._isdigit(x_, y_):
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# this is suboptimal because we will process the
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# numeral adjacent to a symbol three times at max
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# like in the following case
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# ...*...
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# ..123..
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# however this saves some lines of code.
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# we'll just use memoization with a dict to make sure
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# we don't add the same numeral more than once
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num, coords = self._extend_digit_to_numeral(x_, y_)
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tmp[coords] = num
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return list(tmp.values())
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def _extend_digit_to_numeral(self, y, x) -> (int, tuple):
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'''
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this returns the numeral itself plus coordinates where the numeral
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has been found (y, x1..xn)
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'''
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found_digit = self.grid[y][x]
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x_array = [x]
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x_ = x-1
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proceed = True
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while proceed:
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if self._isdigit(y, x_):
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x_array.append(x_)
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found_digit = self.grid[y][x_] + found_digit
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x_ -= 1
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continue
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proceed = False
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x_ = x+1
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proceed = True
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while proceed:
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if self._isdigit(y, x_):
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x_array.append(x_)
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found_digit += self.grid[y][x_]
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x_ += 1
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continue
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proceed = False
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x_array.sort()
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return int(found_digit), (y,) + tuple(x_array)
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def _find_part_numbers(self):
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symbols = self._find_all_symbols()
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for symbol in symbols:
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found_numbers = self._find_adjacent_numerals(symbol[0], symbol[1])
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self.part_numbers.extend(found_numbers)
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def _find_all_gears(self):
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symbols = self._find_all_symbols()
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for symbol in symbols:
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if self.grid[symbol[0]][symbol[1]] == '*':
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numerals = self._find_adjacent_numerals(symbol[0], symbol[1])
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if len(numerals) == 2:
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# there are exactly to numerals adjacent
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# to a '*' symbol, so this is a gear
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self.gears.append(tuple(numerals))
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def find_sum_part_numbers(self):
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self._find_part_numbers()
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return sum(self.part_numbers)
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def find_sum_gears(self):
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self._find_all_gears()
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total = 0
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for g in self.gears:
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ratio = g[0] * g[1]
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total += ratio
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return total
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if __name__ == '__main__':
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r = tools.Reader('input.txt')
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lines = r.read()
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scheme = Scheme(lines)
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x = scheme.find_sum_part_numbers()
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print(x)
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y = scheme.find_sum_gears()
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print(y)
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