From 9cd7cba1c2acf0836d2db3e4dee4d9d2f94e4742 Mon Sep 17 00:00:00 2001
From: fettlaus <_Ox46K:26i?>
Date: Sat, 7 Dec 2019 01:53:22 +0100
Subject: [PATCH] Finally added day 3

---
 advent.py    |  2 ++
 days/day3.py | 48 ++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/advent.py b/advent.py
index 575b29b..1630b1b 100644
--- a/advent.py
+++ b/advent.py
@@ -8,6 +8,8 @@ def suite():
     suite.addTest(Day1('test_day1b'))
     suite.addTest(Day2('test_day2a'))
     suite.addTest(Day2('test_day2b'))
+    suite.addTest(Day3('test_day3a'))
+    suite.addTest(Day3('test_day3b'))
     suite.addTest(Day4('test_day4a'))
     suite.addTest(Day4('test_day4b'))
     suite.addTest(Day5('test_day5a'))
diff --git a/days/day3.py b/days/day3.py
index d308f28..9150d1d 100644
--- a/days/day3.py
+++ b/days/day3.py
@@ -1,11 +1,55 @@
 import unittest
 import os
+import sys
 
 
 class Day3(unittest.TestCase):
     inputfile = os.path.join(os.path.dirname(__file__), "input/day3_input")
 
+    def draw_path(self, inst):
+        path = set()
+        dists = {}
+        cnt = 0
+        ptr = (0, 0)
+        for d, l in ((x[0], x[1:]) for x in inst.split(',')):
+            for _ in range(int(l)):
+                if d == 'D':
+                    ptr = (ptr[0], ptr[1] - 1)
+                elif d == 'R':
+                    ptr = (ptr[0] + 1, ptr[1])
+                elif d == 'U':
+                    ptr = (ptr[0], ptr[1] + 1)
+                else:
+                    ptr = (ptr[0] - 1, ptr[1])
+                cnt += 1
+                if ptr not in dists or dists[ptr] > cnt:
+                    dists[ptr] = cnt
+                path.add(ptr)
+        return (path, dists)
+
     def test_day3a(self):
+        paths = []
+        result = sys.maxsize
+
+        with open(self.inputfile) as fp:
+            for line in fp.readlines():
+                paths.append(self.draw_path(line)[0])
+        for x, y in paths[0].intersection(paths[1]):
+            dist = abs(x) + abs(y)
+            result = dist if dist < result else result
+        self.assertEqual(result, 399)
+
+    def test_day3b(self):
+        paths = []
+        distances = []
+        result = sys.maxsize
+
         with open(self.inputfile) as fp:
-            steps = fp.readline().split(',')
-            pass
+            for line in fp.readlines():
+                computed = self.draw_path(line)
+                paths.append(computed[0])
+                distances.append(computed[1])
+        for point in paths[0].intersection(paths[1]):
+            dist = distances[0][point] + distances[1][point]
+            result = dist if dist < result else result
+        self.assertEqual(result, 15678)