[2016 Day 1 (Part 1 + 2)] [python] Alternate implementation #6
Description
First of all, thank you very much for this substantial archive of AOC solutions.
I think a little differently, so while your unit-circle implementation of this day's puzzle made sense to me it, seemed a little complicated for such an easy challenge. This is my alternate solution to this day (both parts), which uses lists to store the directions and delta values and uses list.index() to find the element number to use in each list and sub-list.
import time
def main():
with open("day1.txt", mode="rt") as f:
direc = f.read().split(", ")
print(f"Input has {len(direc)} directions")
instrs = ["R", "L"]
direcs = ["0", "+x", "+y", "-x", "-y"]
xydelt = [[[1, 0], [0, -1], [1, 0], [0, 1], [-1, 0]],
[[-1, 0], [0, 1], [-1, 0], [0, -1], [1, 0]]]
xyhdng = [["+x", "-y", "+x", "+y", "-x"],
["-x", "+y", "-x", "-y", "+x"]]
visited = [[0, 0]]
got1st = False
x, y, h = (0, 0, "0")
for dx in range(len(direc)):
d = direc[dx][0]
xydir = instrs.index(d)
hding = direcs.index(h)
xynum = int(direc[dx][1:])
dx, dy = xydelt[xydir][hding][0], xydelt[xydir][hding][1]
for _ in range(xynum):
x += dx
y += dy
if not [x, y] in visited:
visited.append([x, y])
elif not got1st:
print(f"{x},{y} first to visit twice,dist={abs(x)+abs(y)}")
got1st = True
h = xyhdng[xydir][hding]
print(f"Final x={x},y={y},dist={abs(x)+abs(y)},visited={len(visited)}")
if __name__ == "__main__":
t1 = time.perf_counter()
main()
t2 = time.perf_counter()
print(f"Execution time: {t2 - t1:0.4f} seconds")
Output from my solution with my inputs on an i7-6700K CPU @ 4.00GHz under Win10:
Input has 168 directions
148,-34 first to visit twice,dist=182
Final x=113,y=123,dist=236,visited=952
Execution time: 0.0074 seconds