Nim

Huh, I didn’t expect two easy days in a row.
Part 1 is a range check. Part 2 is a range merge.

Runtime: ~720 µs

type
  AOCSolution[T,U] = tuple[part1: T, part2: U]

proc merge[T](ranges: var seq[Slice[T]]) =
  ranges.sort(cmp = proc(r1, r2: Slice[T]): int = cmp(r1.a, r2.a))
  var merged = @[ranges[0]]
  for range in ranges.toOpenArray(1, ranges.high):
    if range.a <= merged[^1].b:
      if range.b > merged[^1].b:
        merged[^1].b = range.b
    else:
      merged.add range
  ranges = merged

proc solve(input: string): AOCSolution[int, int] =
  let chunks = input.split("\n\n")
  var freshRanges = chunks[0].splitLines().mapIt:
    let t = it.split('-'); t[0].parseInt .. t[1].parseInt

  freshRanges.merge()

  block p1:
    let availableFood = chunks[1].splitLines().mapIt(parseInt it)
    for food in availableFood:
      for range in freshRanges:
        if food in range:
          inc result.part1
          break

  block p2:
    for range in freshRanges:
      result.part2 += range.b-range.a+1

Full solution at Codeberg: solution.nim

C

Repo

Sweet one. Glad the merge could be done with one n²/2 scan and no sorting or moving, which will make the assembly port a bit easier. Speaking of which, I’m still at day 3 there, fighting not the puzzles but the 64K .COM file limit!

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <assert.h>

#define MR	256

#define MIN(a,b)	((a)<(b)?(a):(b))
#define MAX(a,b)	((a)>(b)?(a):(b))

struct range { uint64_t lo, hi; };

static struct range rs[MR];
static int nrs;

int
main()
{
	uint64_t p1=0,p2=0, val;
	int i,j;
	char buf[64];

        for (; fgets(buf, sizeof(buf), stdin); nrs++) {
                assert(nrs < MR);
                if (sscanf(buf, "%lu-%lu", &rs[nrs].lo, &rs[nrs].hi) != 2)
                        break;
        }

	for (i=0; i<nrs-1; i++)
	for (j=i+1; j<nrs; j++)
		if (rs[i].lo <= rs[j].hi && rs[i].hi >= rs[j].lo) {
			rs[j].lo = MIN(rs[i].lo, rs[j].lo);
			rs[j].hi = MAX(rs[i].hi, rs[j].hi);
			rs[i].lo = rs[i].hi = 0;
		}

	while (scanf("%lu", &val) == 1)
		for (i=0; i<nrs; i++)
			if (val >= rs[i].lo && val <= rs[i].hi)
				{ p1++; break; }
	
	for (i=0; i<nrs; i++)
		if (rs[i].lo)
			p2 += rs[i].hi - rs[i].lo + 1;
	
	printf("05: %lu %lu\n", p1, p2);
}