C 2022/Day 4 init

2022/day04/README.org

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+** --- Day 4: Camp Cleanup ---
+Space needs to be cleared before the last supplies can be unloaded from
+the ships, and so several Elves have been assigned the job of cleaning
+up sections of the camp. Every section has a unique /ID number/, and
+each Elf is assigned a range of section IDs.
+
+However, as some of the Elves compare their section assignments with
+each other, they've noticed that many of the assignments /overlap/. To
+try to quickly find overlaps and reduce duplicated effort, the Elves
+pair up and make a /big list of the section assignments for each pair/
+(your puzzle input).
+
+For example, consider the following list of section assignment pairs:
+
+#+begin_example
+2-4,6-8
+2-3,4-5
+5-7,7-9
+2-8,3-7
+6-6,4-6
+2-6,4-8
+#+end_example
+
+For the first few pairs, this list means:
+
+- Within the first pair of Elves, the first Elf was assigned sections
+  =2-4= (sections =2=, =3=, and =4=), while the second Elf was assigned
+  sections =6-8= (sections =6=, =7=, =8=).
+- The Elves in the second pair were each assigned two sections.
+- The Elves in the third pair were each assigned three sections: one got
+  sections =5=, =6=, and =7=, while the other also got =7=, plus =8= and
+  =9=.
+
+This example list uses single-digit section IDs to make it easier to
+draw; your actual list might contain larger numbers. Visually, these
+pairs of section assignments look like this:
+
+#+begin_example
+.234.....  2-4
+.....678.  6-8
+
+.23......  2-3
+...45....  4-5
+
+....567..  5-7
+......789  7-9
+
+.2345678.  2-8
+..34567..  3-7
+
+.....6...  6-6
+...456...  4-6
+
+.23456...  2-6
+...45678.  4-8
+#+end_example
+
+Some of the pairs have noticed that one of their assignments /fully
+contains/ the other. For example, =2-8= fully contains =3-7=, and =6-6=
+is fully contained by =4-6=. In pairs where one assignment fully
+contains the other, one Elf in the pair would be exclusively cleaning
+sections their partner will already be cleaning, so these seem like the
+most in need of reconsideration. In this example, there are =2= such
+pairs.
+
+/In how many assignment pairs does one range fully contain the other?/
+
+To begin, [[file:4/input][get your puzzle input]].
+
+Answer:
+
+You can also [Shareon
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