2021 - Day 5

🎄 Advent of Code in Zef 🎄

https://adventofcode.com/2021/day/5

data = """  
0,9 -> 5,9  
8,0 -> 0,8  
9,4 -> 3,4  
2,2 -> 2,1  
7,0 -> 7,4  
6,4 -> 2,0  
0,9 -> 2,9  
3,4 -> 1,4  
0,0 -> 8,8  
5,5 -> 8,2  
"""  
  
  
def parse_line(s: str)->tuple:  
    return (s  
    | split[' -> ']  
    | map[split[','] | map[int]]  
    | collect  
    )  
  
  
def to_points(rs):  
    r1, r2 = rs  
    f = lambda a, b: a|repeat if a==b else range(min(a,b), max(a,b)+1)  
    return (f(r1[0], r2[0]), f(r1[1], r2[1])) | zip | collect  
  
  
result = (data  
 | split['\n']  
 | trim['']  
 | map[parse_line]    # convert each line to e.g. [ [0, 9], [5, 9] ]  
 | filter[unpack[lambda r1, r2: r1[0] == r2[0] or r1[1] == r2[1]]]     # only non-diagonal lines for now  
 | map[to_points]     # given the end points, return a list of all points in between the ends  
 | concat  
 | frequencies        # count how often a point occurs here  
 | values  
 | filter[greater_than[1]]  # how many points have overlapping lines  
 | length  
 | collect  
)