day 4 solution

bin/d4/dune

@@ -0,0 +1,4 @@
+(executable
+ (public_name d4)
+ (name main)
+ (libraries core utils))

bin/d4/main.ml

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+let is_full (start1, end1) (start2, end2) =
+    (start1 >= start2 && end1 <= end2) ||
+    (start2 >= start1 && end2 <= end1)
+
+let is_partial (start1, end1) (start2, end2) =
+    (start1 >= start2 && start1 <= end2) ||
+    (start2 >= start1 && start2 <= end1)
+
+open Utils
+
+let split_pair c s = String.split_on_char c s |> pair_of_list
+let get_elves = split_pair ','
+let get_range range = range |> split_pair '-' |> map_pair int_of_string
+let parse row = row |> get_elves |> map_pair get_range
+
+let count_overlapping f l = l |> List.filter (uncurry f) |> List.length
+
+let input = read_file "bin/d4/input.txt" |> List.map parse
+let _ = "\n1: " ^ (string_of_int (input |> count_overlapping is_full)) ^
+        "\n2: " ^ (string_of_int (input |> count_overlapping is_partial)) |> print_endline ;;