day 16

r0f1 · r0f1 · commit 21c93bf02464 · 2020-12-19T13:39:01.000+01:00
diff --git a/README.md b/README.md
@@ -17,7 +17,7 @@
 |[13](https://adventofcode.com/2020/day/13)|Shuttle Search|[py](/day13/main.py)|
 |[14](https://adventofcode.com/2020/day/14)|Docking Data|[py](/day14/main.py)|
 |[15](https://adventofcode.com/2020/day/15)|Rambunctious Recitation|[py](/day15/main.py), [alt](/day15/alt.py)|
-|[16](https://adventofcode.com/2020/day/16)|-|-|
+|[16](https://adventofcode.com/2020/day/16)|Ticket Translation|[py](/day16/main.py), [alt](/day16/alt.py)|
 |[17](https://adventofcode.com/2020/day/17)|-|-|
 |[18](https://adventofcode.com/2020/day/18)|-|-|
 |[19](https://adventofcode.com/2020/day/19)|-|-|
diff --git a/day16/alt.py b/day16/alt.py
@@ -0,0 +1,29 @@
+import math
+import re
+
+import numpy as np
+from scipy.sparse import csr_matrix
+from scipy.sparse.csgraph import maximum_bipartite_matching
+
+with open('input.txt') as f:
+    ls = [line.strip() for line in f]
+
+ranges = [list(map(int, re.findall('\d+', x))) for x in ls[:20]]
+your = np.array([int(x) for x in ls[22].split(',')], dtype=np.int64)
+nearby = [list(map(int, re.findall('\d+', x))) for x in ls[25:]]
+
+# Part one
+valid = set()
+for t1, t2, t3, t4 in ranges:
+    valid |= set(range(t1, t2 + 1))
+    valid |= set(range(t3, t4 + 1))
+
+print(sum(n for l in nearby for n in l if n not in valid))
+
+# Part two
+valids = [l for l in nearby if all(n in valid for n in l)]
+loc = [[all((t1 <= l[j] <= t2) or (t3 <= l[j] <= t4) for l in valids)
+        for t1, t2, t3, t4 in ranges]
+       for j in range(20)]
+m = maximum_bipartite_matching(csr_matrix(loc))
+print(your[m[:6]].prod())
diff --git a/day16/main.py b/day16/main.py
@@ -0,0 +1,60 @@
+import numpy as np
+
+with open("input.txt") as f:
+    lines = [x.strip() for x in f]
+
+sep1 = "your ticket:"
+sep2 = "nearby tickets:"
+
+part1 = lines[:lines.index(sep1)-1]
+part2 = [int(n) for n in lines[lines.index(sep1)+1].split(",")]
+part3 = lines[lines.index(sep2)+1:]
+
+alloweds = []
+for line in part1:
+    a = set()
+    ranges = line.split(": ")[1]
+    for r in ranges.split(" or "):
+        bounds = r.split("-")
+        lb, ub = int(bounds[0]), int(bounds[1])
+        for i in range(lb, ub+1):
+            a.add(i)
+    alloweds.append(a)
+
+score = []
+c = len(part1)
+poss_mat = np.ones((c,c), dtype=np.uint8)
+
+for line in part3:
+    okay = True
+    numbers = [int(n) for n in line.split(",")]
+    for n in numbers:
+        if not any(n in a for a in alloweds):
+            score.append(n)
+            okay = False
+    if okay:
+        for field_idx, n in enumerate(numbers):
+            for j, a in enumerate(alloweds):
+                if n not in a:
+                    poss_mat[field_idx][j] = 0
+
+print(sum(score))
+
+change = True
+seen = set()
+while change:
+    change = False
+    for i, row in enumerate(poss_mat):
+        if sum(row) == 1 and i not in seen:
+            seen.add(i)
+            change = True
+            col = np.argmax(row)
+            poss_mat[:, col] = 0
+            poss_mat[i, col] = 1
+
+res = 1
+for j, row in enumerate(poss_mat):
+    if np.argmax(row) < 6:
+        res *= part2[j]
+
+print(res)
