p3.py

#!/usr/bin/env python3
# -*- coding: utf8 -*-

import sys

wires = []
for line in open(sys.argv[1],'r').readlines():
    parts = line.split(',')
    wire = {}
    r = 0
    c = 0
    steps = 1
    for part in parts:
        direction = part[0]
        length = int(part[1:])
        for i in range(length):
            if direction == "D":
                r = r + 1
            elif direction == "U":
                r = r - 1
            elif direction == "L":
                c = c - 1
            elif direction == "R":
                c = c + 1

            wire[(r,c)] = steps + i
        steps = steps + length

    wires.append(wire)

w1k = set(wires[0].keys())
w2k = set(wires[1].keys())
intersections = w1k & w2k

print("pt 1:", min(abs(i[0]) + abs(i[1]) for i in intersections))
print("pt 2:", min(wires[0][i] + wires[1][i] for i in intersections))