“Some kind of electrical surge seems to have fried them. I’ll try to get them online soon.”

Github: GCaggianese/AoC-2025/D3

Puzzle Day 3: Lobby

Part One:

1. int jolt = 0;
2. make a list and a copy of it of the input, og, aux1
3. aux1 will drop the last value ex.: 987654321111118 → 98765432111111
4. you’ll take the max here → jolt += aux1.max*10
5. create a 2nd list aux2, slice of the og from the next position of the max before ex.: 98765432111111 max = 9 → aux2 = 87654321111118
6. you’ll take the max here → jolt += aux2.max

Part Two:

1. long jolt = 0;
2. multiplier = 10^11 (since we’re building a 12-digit number)
3. for i = 0 to 11 (picking 12 digits):
   • remaining~needed~ = 12 - i
   • window = og[0 .. og.length - remaining~needed~ + 1] (leave enough elements for future picks) ex.: first pick from 234234234234278, need 12 digits window = [2,3,4,2] (must leave 11 for later)
   • pick maxVal from window → jolt += maxVal * multiplier
   • slice og from maxIdx+1 onward (discard everything up to & including pick) ex.: picked 4 at idx 2 → og becomes [2,3,4,2,3,4,2,7,8]
   • multiplier /= 10
4. Summary: pick the highest available digit that still leaves enough digits remaining to complete 12 picks