part 1 day 8

8/1.py

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+# Returns the rise/run
+def slope(a: (int, int), b: (int, int)) -> (int, int):
+    return (b[0] - a[0], b[1] - a[1])
+
+def inside(pos: (int, int), max: (int, int)) -> bool:
+    return 0 <= pos[0] < max[0] and 0 <= pos[1] < max[1]
+
+if __name__ == '__main__':
+    with open('input.data') as file:
+        grid = [line.strip() for line in file]
+
+    nodes = {}
+    for y, row in enumerate(grid):
+        for x, c in enumerate(row):
+            if c == '.':
+                continue
+            if c in nodes:
+                nodes[c].append((x,y))
+            else:
+                nodes[c] = [(x,y)]
+    antinodes = set()
+    for freq in nodes:
+        print(f'Find all possible slopes given the starting positions of {freq}')
+        for x,y in nodes[freq]:
+            cur = (x,y)
+            slopes = [slope(cur, (ox, oy)) for ox, oy in nodes[freq]]
+            slopes = list(filter(lambda i: i != (0,0), slopes))
+            antis  = [(x + (i[0]*2), y+ (i[1]*2)) for i in slopes]
+            antis  = list(filter(lambda i: inside(i, (len(grid[0]), len(grid[1]))), antis))
+            for a in antis:
+                if a in nodes:
+                    print('found', a)
+                antinodes.add(a)
+            print(cur, '-->', slopes, 'antis ==>', antis)
+    print('Total', len(antinodes))
+    

8/sample.data

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+............
+........0...
+.....0......
+.......0....
+....0.......
+......A.....
+............
+............
+........A...
+.........A..
+............
+............