136 lines
3.2 KiB
Python
136 lines
3.2 KiB
Python
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#!/usr/bin/env python
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# 2021 - Advent Of Code - 5 part 2
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def parse_file(file):
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horizontal_lines = []
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vertical_lines = []
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diagonal_lines = []
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with open(file) as f:
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for l in f.readlines():
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p1, p2 = l.strip().split(' -> ')
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strx1, stry1 = p1.split(',')
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strx2, stry2 = p2.split(',')
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# filter horizontal and vertical lines only
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p1 = (int(strx1), int(stry1))
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p2 = (int(strx2), int(stry2))
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if strx1 == strx2:
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vertical_lines.append([p1, p2])
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elif stry1 == stry2:
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horizontal_lines.append([p1, p2])
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else:
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diagonal_lines.append([p1, p2])
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return horizontal_lines, vertical_lines, diagonal_lines
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def draw_horizontal(g, hline):
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# print(f'drawing hline: {hline}')
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if hline[0][0] < hline[1][0]: # left -> right
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start_point = hline[0]
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end_point = hline[1]
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else:
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start_point = hline[1]
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end_point = hline[0]
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ly = start_point[1]
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# print(f'drawing from {start_point[0]} to {end_point[0]}')
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for lx in range(start_point[0], end_point[0]+1):
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g[ly][lx] += 1
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def draw_vertical(g, vline):
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# print(f'drawing vline: {vline}')
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if vline[0][1] < vline[1][1]: # up -> down
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start_point = vline[0]
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end_point = vline[1]
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else:
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start_point = vline[1]
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end_point = vline[0]
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lx = start_point[0]
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# print(f'drawing from {start_point[0]} to {end_point[0]}')
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for ly in range(start_point[1], end_point[1]+1):
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g[ly][lx] += 1
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def draw_diagonal(g, dline):
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x1 = dline[0][0]
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y1 = dline[0][1]
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x2 = dline[1][0]
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y2 = dline[1][1]
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hdir = 1
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if x1 > x2:
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hdir = -1
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vdir = 1
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if y1 > y2:
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vdir = -1
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lx = x1
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ly = y1
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for i in range(abs(x2-x1)+1):
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g[ly][lx] += 1
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lx += hdir
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ly += vdir
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hlines, vlines, dlines = parse_file('input.txt')
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print(f'horizontal lines parsed: {len(hlines)}')
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print(f'vertical lines parsed: {len(vlines)}')
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print(f'diagonal lines parsed: {len(dlines)}')
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# detect size of the grid (assumed 1000x1000, but why not ;-) )
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maxx = 0
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maxy = 0
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for line in hlines + vlines + dlines:
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startp = line[0]
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endp = line[1]
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if startp[0] > maxx:
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maxx = startp[0]
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if endp[0] > maxx:
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maxx = endp[0]
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if startp[1] > maxy:
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maxy = startp[1]
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if endp[1] > maxy:
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maxy = endp[1]
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print(f'detected grid size: {maxx} x {maxy}')
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grid = [[0] * (maxx+1) for _ in range(maxy+1)]
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# draw
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for hl in hlines:
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draw_horizontal(grid, hl)
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for vl in vlines:
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draw_vertical(grid, vl)
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for dl in dlines:
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draw_diagonal(grid, dl)
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# count points
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points = 0
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for y in range(maxy+1):
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for x in range(maxx+1):
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if grid[y][x] > 1:
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points += 1
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print(f'There\'s {points} points with at least two lines')
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# bonus (or debug with the sample), draw the grid
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# print(' ', end='')
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# for y in range(maxy+1):
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# print(y, end='')
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# print()
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#
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# for y in range(maxy+1):
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# print(f'{y} ', end='')
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# for x in range(maxx+1):
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# if grid[y][x] == 0:
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# print('.', end='')
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# else:
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# print(str(grid[y][x]), end='')
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# print()
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