diff --git a/2025/day03/problem b/2025/day03/problem new file mode 100644 index 0000000..a505d77 --- /dev/null +++ b/2025/day03/problem @@ -0,0 +1,130 @@ +Advent of Code + +br0xen [7](AoC++) 6* + +--- Day 3: Lobby --- + + You descend a short staircase, enter the surprisingly vast lobby, and are + quickly cleared by the security checkpoint. When you get to the main + elevators, however, you discover that each one has a red light above it: + they're all offline. + + "Sorry about that," an Elf apologizes as she tinkers with a nearby control + panel. "Some kind of electrical surge seems to have fried them. I'll try + to get them online soon." + + You explain your need to get further underground. "Well, you could at + least take the escalator down to the printing department, not that you'd + get much further than that without the elevators working. That is, you + could if the escalator weren't also offline." + + "But, don't worry! It's not fried; it just needs power. Maybe you can get + it running while I keep working on the elevators." + + There are batteries nearby that can supply emergency power to the + escalator for just such an occasion. The batteries are each labeled with + their [16]joltage rating, a value from 1 to 9. You make a note of their + joltage ratings (your puzzle input). For example: + + 987654321111111 + 811111111111119 + 234234234234278 + 818181911112111 + + The batteries are arranged into banks; each line of digits in your input + corresponds to a single bank of batteries. Within each bank, you need to + turn on exactly two batteries; the joltage that the bank produces is equal + to the number formed by the digits on the batteries you've turned on. For + example, if you have a bank like 12345 and you turn on batteries 2 and 4, + the bank would produce 24 jolts. (You cannot rearrange batteries.) + + You'll need to find the largest possible joltage each bank can produce. In + the above example: + + • In 987654321111111, you can make the largest joltage possible, 98, by + turning on the first two batteries. + • In 811111111111119, you can make the largest joltage possible by + turning on the batteries labeled 8 and 9, producing 89 jolts. + • In 234234234234278, you can make 78 by turning on the last two + batteries (marked 7 and 8). + • In 818181911112111, the largest joltage you can produce is 92. + + The total output joltage is the sum of the maximum joltage from each bank, + so in this example, the total output joltage is 98 + 89 + 78 + 92 = 357. + + There are many batteries in front of you. Find the maximum joltage + possible from each bank; what is the total output joltage? + + Your puzzle answer was 17113. + +--- Part Two --- + + The escalator doesn't move. The Elf explains that it probably needs more + joltage to overcome the [17]static friction of the system and hits the big + red "joltage limit safety override" button. You lose count of the number + of times she needs to confirm "yes, I'm sure" and decorate the lobby a bit + while you wait. + + Now, you need to make the largest joltage by turning on exactly twelve + batteries within each bank. + + The joltage output for the bank is still the number formed by the digits + of the batteries you've turned on; the only difference is that now there + will be 12 digits in each bank's joltage output instead of two. + + Consider again the example from before: + + 987654321111111 + 811111111111119 + 234234234234278 + 818181911112111 + + Now, the joltages are much larger: + + • In 987654321111111, the largest joltage can be found by turning on + everything except some 1s at the end to produce 987654321111. + • In the digit sequence 811111111111119, the largest joltage can be + found by turning on everything except some 1s, producing 811111111119. + • In 234234234234278, the largest joltage can be found by turning on + everything except a 2 battery, a 3 battery, and another 2 battery near + the start to produce 434234234278. + • In 818181911112111, the joltage 888911112111 is produced by turning on + everything except some 1s near the front. + + The total output joltage is now much larger: 987654321111 + 811111111119 + + 434234234278 + 888911112111 = 3121910778619. + + What is the new total output joltage? + + Your puzzle answer was 169709990062889. + + Both parts of this puzzle are complete! They provide two gold stars: ** + + At this point, you should [18]return to your Advent calendar and try + another puzzle. + + If you still want to see it, you can [19]get your puzzle input. + +References + + Visible links + 1. https://adventofcode.com/ + 2. https://adventofcode.com/2025/about + 3. https://adventofcode.com/2025/events + 5. https://adventofcode.com/2025/settings + 6. https://adventofcode.com/2025/auth/logout + 7. Advent of Code Supporter + https://adventofcode.com/2025/support + 8. https://adventofcode.com/2025 + 9. https://adventofcode.com/2025 + 10. https://adventofcode.com/2025/support + 11. https://adventofcode.com/2025/sponsors + 12. https://adventofcode.com/2025/leaderboard/private + 13. https://adventofcode.com/2025/stats + 14. https://adventofcode.com/2025/sponsors + 15. https://adventofcode.com/2025/sponsors/redirect?url=https%3A%2F%2Ffullscript%2Ecom%2Fcareers + 16. https://adventofcode.com/2020/day/10 + 17. https://en.wikipedia.org/wiki/Static_friction + 18. https://adventofcode.com/2025 + 19. https://adventofcode.com/2025/day/3/input + 22. javascript:void(0);