summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--d7.nim35
1 files changed, 35 insertions, 0 deletions
diff --git a/d7.nim b/d7.nim
new file mode 100644
index 0000000..536897d
--- /dev/null
+++ b/d7.nim
@@ -0,0 +1,35 @@
+import std/algorithm, std/os, std/sugar, std/strutils, std/math
+
+proc read_crabs(filename: string): seq[int] =
+ let f = open(filename)
+ defer: f.close()
+ result = collect:
+ for crab in f.read_all().split(','):
+ parse_int(crab.strip())
+
+func part1(crabs: seq[int]): int =
+ let median = sorted(crabs)[len(crabs) div 2]
+ for crab in crabs:
+ result += abs(crab - median)
+
+func part2_fuel(crabs: seq[int], pos: int): int =
+ for crab in crabs:
+ let dist = abs(crab - pos)
+ result += dist * (dist + 1) div 2
+
+func part2(crabs: seq[int]): int =
+ let
+ l = len(crabs)
+ s = sum(crabs)
+ var c = 0
+ for crab in crabs:
+ if crab * l > s: inc c
+ return part2_fuel(crabs, (s + c) div l)
+
+when is_main_module:
+ var filename: string = "7.in"
+ if param_count() == 1:
+ filename = param_str(1)
+ let crabs = read_crabs(filename)
+ echo part1(crabs)
+ echo part2(crabs)