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 --- 2020/06/part2.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 2020/06/part2.c (limited to '2020/06/part2.c') diff --git a/2020/06/part2.c b/2020/06/part2.c new file mode 100644 index 0000000..11c8469 --- /dev/null +++ b/2020/06/part2.c @@ -0,0 +1,44 @@ +#include + +int plane_count(const char *filename) +{ + FILE *file = fopen(filename, "r"); + + // Include space for newline and string terminator + char buffer[32] = { 0 }; + + int tot = 0; + unsigned int current = 0xffffffff; + + while (fgets(buffer, 32, file)) { + if (buffer[0] == '\n') { + if (current != 0xffffffff) { + tot += __builtin_popcount(current); + current = 0xffffffff; + } + + continue; + } + + unsigned int tmp = 0; + char *p = buffer; + do { + tmp |= 1 << (*p - 97); + } while (*++p != '\n'); + + current &= tmp; + } + + fclose(file); + + if (current != 0xffffffff) { + tot += __builtin_popcount(current); + } + + return tot; +} + +int main(int argc, char *argv[]) +{ + printf("%i\n", plane_count(argv[argc - 1])); +} -- cgit v1.2.3