From baf4910870a6e8999802b9a4a22eabd4142a34e3 Mon Sep 17 00:00:00 2001 From: Bond_009 Date: Thu, 1 Dec 2022 22:30:22 +0100 Subject: Move all Advent of Codes into one repo --- 2020/03/part2.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 2020/03/part2.c (limited to '2020/03/part2.c') diff --git a/2020/03/part2.c b/2020/03/part2.c new file mode 100644 index 0000000..bae8654 --- /dev/null +++ b/2020/03/part2.c @@ -0,0 +1,41 @@ +#include +#include +#include +#include + +int count_trees(int inc_right, int inc_down, const char *filename) +{ + FILE *file = fopen(filename, "r"); + + // Include space for newline and string terminator + char buffer[64] = { 0 }; + // Start is always safe + fgets(buffer, 64, file); + // strlen includes the newline + int width = strchr(buffer, '\n') - buffer; + + int pos = inc_right; + int hit = 0; + for (int i = 1; fgets(buffer, 64, file); i++) { + if (inc_down != 1 && i % inc_down != 0) { + continue; + } + + if (buffer[pos] == '#') { + hit++; + } + + pos = (pos + inc_right) % width; + } + + fclose(file); + + return hit; +} + +int main(int argc, char *argv[]) +{ + char *arg = argv[argc - 1]; + long mul = (long)count_trees(1, 1, arg) * count_trees(3, 1, arg) * count_trees(5, 1, arg) * count_trees(7, 1, arg) * count_trees(1, 2, arg); + printf("%li\n", mul); +} -- cgit v1.2.3