days 1-7

1 files changed, 23 insertions, 0 deletions

diff --git a/3.py b/3.py
new file mode 100644
index 0000000..e7bb2d1
--- /dev/null
+++ b/3.py
@@ -0,0 +1,23 @@
+with open('3.in') as f:
+    rucksacks = [line.rstrip() for line in f]
+
+def priority(itm):
+    if itm.islower():
+        return ord(common) - ord('a') + 1
+    else:
+        return ord(common) - ord('A') + 27
+
+total = 0
+for rucksack in rucksacks:
+    half = len(rucksack) // 2
+    a, b = set(rucksack[:half]), set(rucksack[half:])
+    common = set.intersection(a, b).pop()
+    total += priority(common)
+print(total)
+
+total = 0
+for i in range(0, len(rucksacks), 3):
+    a, b, c = map(set, rucksacks[i:i+3])
+    common = set.intersection(a, set.intersection(b, c)).pop()
+    total += priority(common)
+print(total)