AdventOfCode2023/day_4/solution.d

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2023-12-04 13:44:56 +00:00
import std.stdio;
import std.algorithm;
import std.string;
import std.array;
import std.conv;
import std.uni;
int countMatchingNumbers(string card) {
const string[] parts = split(card, "|");
const int[] winningNums = split(parts[0], ":")[1].split(" ")
.filter!(s => s.length > 0)
.map!(s => s.strip.to!int)
.array;
return parts[1].split(" ")
.filter!(s => s.length > 0)
.map!(s => s.strip.to!int)
.map!(n => canFind(winningNums, n) ? 1 : 0)
.sum;
}
void part1() {
File("input.txt").byLineCopy()
.map!(s => countMatchingNumbers(s))
.map!(n => n < 2 ? n : 1 << n-1)
.sum.writeln;
}
void part2() {
int[] matchesPerCard = File("input.txt").byLineCopy().map!countMatchingNumbers.array;
int[] cardCounts = new int[matchesPerCard.length];
cardCounts[] = 1; // Set all card counts to 1 initially.
for (int card = 0; card < cardCounts.length; card++) {
for (int i = 1; i < matchesPerCard[card] + 1; i++) {
cardCounts[card+i] += cardCounts[card];
}
}
cardCounts.sum.writeln;
}
void main() {
part1();
part2();
}