Move 2015 out of the way.

2015/day-13/input.txt

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+Alice would lose 2 happiness units by sitting next to Bob.
+Alice would lose 62 happiness units by sitting next to Carol.
+Alice would gain 65 happiness units by sitting next to David.
+Alice would gain 21 happiness units by sitting next to Eric.
+Alice would lose 81 happiness units by sitting next to Frank.
+Alice would lose 4 happiness units by sitting next to George.
+Alice would lose 80 happiness units by sitting next to Mallory.
+Bob would gain 93 happiness units by sitting next to Alice.
+Bob would gain 19 happiness units by sitting next to Carol.
+Bob would gain 5 happiness units by sitting next to David.
+Bob would gain 49 happiness units by sitting next to Eric.
+Bob would gain 68 happiness units by sitting next to Frank.
+Bob would gain 23 happiness units by sitting next to George.
+Bob would gain 29 happiness units by sitting next to Mallory.
+Carol would lose 54 happiness units by sitting next to Alice.
+Carol would lose 70 happiness units by sitting next to Bob.
+Carol would lose 37 happiness units by sitting next to David.
+Carol would lose 46 happiness units by sitting next to Eric.
+Carol would gain 33 happiness units by sitting next to Frank.
+Carol would lose 35 happiness units by sitting next to George.
+Carol would gain 10 happiness units by sitting next to Mallory.
+David would gain 43 happiness units by sitting next to Alice.
+David would lose 96 happiness units by sitting next to Bob.
+David would lose 53 happiness units by sitting next to Carol.
+David would lose 30 happiness units by sitting next to Eric.
+David would lose 12 happiness units by sitting next to Frank.
+David would gain 75 happiness units by sitting next to George.
+David would lose 20 happiness units by sitting next to Mallory.
+Eric would gain 8 happiness units by sitting next to Alice.
+Eric would lose 89 happiness units by sitting next to Bob.
+Eric would lose 69 happiness units by sitting next to Carol.
+Eric would lose 34 happiness units by sitting next to David.
+Eric would gain 95 happiness units by sitting next to Frank.
+Eric would gain 34 happiness units by sitting next to George.
+Eric would lose 99 happiness units by sitting next to Mallory.
+Frank would lose 97 happiness units by sitting next to Alice.
+Frank would gain 6 happiness units by sitting next to Bob.
+Frank would lose 9 happiness units by sitting next to Carol.
+Frank would gain 56 happiness units by sitting next to David.
+Frank would lose 17 happiness units by sitting next to Eric.
+Frank would gain 18 happiness units by sitting next to George.
+Frank would lose 56 happiness units by sitting next to Mallory.
+George would gain 45 happiness units by sitting next to Alice.
+George would gain 76 happiness units by sitting next to Bob.
+George would gain 63 happiness units by sitting next to Carol.
+George would gain 54 happiness units by sitting next to David.
+George would gain 54 happiness units by sitting next to Eric.
+George would gain 30 happiness units by sitting next to Frank.
+George would gain 7 happiness units by sitting next to Mallory.
+Mallory would gain 31 happiness units by sitting next to Alice.
+Mallory would lose 32 happiness units by sitting next to Bob.
+Mallory would gain 95 happiness units by sitting next to Carol.
+Mallory would gain 91 happiness units by sitting next to David.
+Mallory would lose 66 happiness units by sitting next to Eric.
+Mallory would lose 75 happiness units by sitting next to Frank.
+Mallory would lose 99 happiness units by sitting next to George.

2015/day-13/solution.py

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+from __future__ import print_function
+import fileinput
+import re
+from itertools import permutations
+
+linePattern = re.compile(r"(\w+) would (gain|lose) (\d+) happiness units by sitting next to (\w+)\.")
+
+ratings = {}
+
+
+# Read the input by regex
+for line in fileinput.input():
+    match = linePattern.match(line)
+    person = match.group(1)
+    if person not in ratings:
+        ratings[person] = {}
+
+    value = int(match.group(3))
+    if match.group(2) == "lose":
+        value *= -1
+
+    target = match.group(4)
+    ratings[person][target] = value
+
+maxHappiness = 0
+maxWithMe = 0
+
+# Compute happiness with everyone present
+for permutation in permutations(list(ratings.keys())):
+    happiness = 0
+    withMe = 0
+
+    for i in range(len(permutation)):
+        target = permutation[i]
+        neighbour1 = permutation[(i + 1) % len(permutation)]
+        neighbour2 = permutation[(i - 1 + len(permutation)) % len(permutation)]
+
+        happiness += ratings[target][neighbour1]
+        if i < len(permutation) - 1:
+            withMe += ratings[target][neighbour1]
+
+        happiness += ratings[target][neighbour2]
+        if i > 0:
+            withMe += ratings[target][neighbour2]
+
+    maxHappiness = max(maxHappiness, happiness)
+    maxWithMe = max(maxWithMe, withMe)
+
+
+print(maxHappiness, maxWithMe)
+