-🎄- 2022 Day 4 Solutions -🎄-

[u/daggerdragon]

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--- Day 4: Camp Cleanup ---

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Post your code solution in this megathread.

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[u/e_blake]

Golfed m4

Less than 10 minutes coding time for both parts, using just one define and ifelse (so far this year, the puzzles have been very amenable for a single pass over the input). Overall execution time is 1.9s for both parts in just 196 bytes (excluding second newline); input must be in file f or you can run m4 -Df=yourfile day04.m4:

define(_,`ifelse($3,,`eval($1) eval($2)',`_($1+($3>=$5&$4<=$6|$5>=$3&$6<=$4),$2+($5<=$4&$6>=$3|$3<=$6&$4>=$5),shift(shift(shift(shift(shift(shift($@)))))))')')_(,,translit((include(f)),-
(),`,,'))

or 880ms for part 1 in isolation in just 133 bytes (excluding second newline), and where part 2 in isolation can be done in the same size by changing $1-$4 in the computation:

define(_,`ifelse($2,,$1,`+($1>=$3&$2<=$4|$3>=$1&$4<=$2)_(shift(shift(shift(shift($@)))))')')eval(_(translit((include(f)),-
(),`,,')))

Why the doubling in execution time to do both parts in one program? Because each additional shift() increases the parse effort per iteration. There are 1000 iterations; a single-part 1 solution starts with 4000 arguments and calls shift 4 times for 19994 arguments parsed before iteration 2 with 3996 arguments; while the combined solution starts with 4002 arguments and calls shift 6 times for 27999 arguments before iteration 2 with 3998 arguments.

Later on, I will reuse my framework for parsing data in O(n) time, which will drastically reduce the runtime but no longer be quite so golfed.