diff --git a/day3/answer2 b/day3/answer2 new file mode 100644 index 0000000..9649634 --- /dev/null +++ b/day3/answer2 @@ -0,0 +1 @@ +75847567 diff --git a/day3/aoc2023d3p2.c b/day3/aoc2023d3p2.c new file mode 100644 index 0000000..7d28815 --- /dev/null +++ b/day3/aoc2023d3p2.c @@ -0,0 +1,186 @@ +#include +#include +#include +#include + +#define MODULE_NAME "aoc2023d3p2" +MODULE_AUTHOR("logan2611"); +MODULE_LICENSE("Dual MIT/GPL"); +MODULE_DESCRIPTION("Advent of Code 2023 Day 3 Part 2 (The Linux Kernel Module)"); +MODULE_VERSION("0.1"); + +const int length = 140; // Number of lines +//const int length = 10; // Number of lines +const int width = length + 1; // Width of lines (including newline, carriage return or null terminator) + +// Parameter that specifies the input file +static char *path = "/tmp/input"; +module_param(path, charp, S_IRUGO); +MODULE_PARM_DESC(path, "The path to the data input."); + +static ssize_t read_input(struct file *file, loff_t pos, size_t n, char *buffer) { + ssize_t bytes_read; + + bytes_read = kernel_read(file, buffer, n, &pos); + if (bytes_read < 0) { + pr_err("%s: Error reading file: %zd\n", MODULE_NAME, bytes_read); + } + + return bytes_read; +} + +static void make_num_string(char *input, char *output, int head, int tail) { + memcpy(output, input + head, tail+1-head); +} + +static int atoi(char *input) { + int ret; + int err = kstrtoint(input, 10, &ret); + if (err < 0) { + //pr_err("%s: Failed to convert string to number: \"%d\"\n", MODULE_NAME, err); + return 0; + } + + return ret; +} + + +static int find_head_number(char *input, int pos) { + while(isdigit(input[pos]) && pos >= 0) { + //pr_info("%s: Scanning head: %c (%d)\n", MODULE_NAME, input[pos], pos); + pos--; + } + //pr_info("%s: Found head: %c (%d)\n", MODULE_NAME, input[pos], pos); + return pos + 1; +} + +static int find_tail_number(char *input, int head) { + while(isdigit(input[head])) { + //pr_info("%s: Scanning tail: %c (%d)\n", MODULE_NAME, input[head], head); + head++; + } + //pr_info("%s: Found tail: %c (%d)\n", MODULE_NAME, input[head], head); + return head - 1; +} + +static int find_adjacent_numbers(char *top, char *middle, char *bottom, int offset) { + int adjacent = 0; + int prod = 1; + + int topskip = 0; + int midskip = 0; + int botskip = 0; + + for(int pos = offset-1; pos <= offset+1; pos++) { + //pr_info("%s: Scanning position %d\n", MODULE_NAME, pos); + if(isdigit(top[pos]) && pos > topskip) { + int head = find_head_number(top, pos); + int tail = find_tail_number(top, head); + + + char numstr[8] = {0}; + make_num_string(top, numstr, head, tail); + + prod *= atoi(numstr); + adjacent++; + topskip = tail; + pr_info("%s: Found adjacent number top: %d %d-%d v:%d\n", MODULE_NAME, pos, head, tail, atoi(numstr)); + } + + if(isdigit(middle[pos]) && pos > midskip) { + int head = find_head_number(middle, pos); + int tail = find_tail_number(middle, head); + + char numstr[8] = {0}; + make_num_string(middle, numstr, head, tail); + + prod *= atoi(numstr); + adjacent++; + midskip = tail; + pr_info("%s: Found adjacent number mid: %d %d-%d v:%d\n", MODULE_NAME, pos, head, tail, atoi(numstr)); + } + + if(isdigit(bottom[pos]) && pos > botskip) { + int head = find_head_number(bottom, pos); + int tail = find_tail_number(bottom, head); + + char numstr[8] = {0}; + make_num_string(bottom, numstr, head, tail); + + prod *= atoi(numstr); + adjacent++; + botskip = tail; + pr_info("%s: Found adjacent number bottom: %d %d-%d v:%d\n", MODULE_NAME, pos, head, tail, atoi(numstr)); + } + } + + if(adjacent == 2) { + return prod; + } else { + return 0; + } +} + + +static int find_stars(char *top, char *middle, char *bottom) { + int beginning = -1; + int sum = 0; + + for(int i = 0; i < width; i++) { + if(middle[i] == '*') { + beginning = i; + pr_info("%s: Found star: %d\n", MODULE_NAME, i); + + sum += find_adjacent_numbers(top, middle, bottom, beginning); + } + } + return sum; +} + + + +static int __init test_init(void) { + struct file *f; + + pr_info("%s: Module loaded\n", MODULE_NAME); + + f = filp_open(path, O_RDONLY, 0); + if(IS_ERR(f)) { + pr_err("%s: Failed to open %s\n", MODULE_NAME, path); + return PTR_ERR(f); + } + + char buf[3][width+1]; + memset(buf, 0, sizeof(buf)); + + read_input(f, 0, width, buf[2]); + + int sum = 0; + + for(int line = 1; line <= length; line++) { + pr_info("%s: %s", MODULE_NAME, buf[2]); + + memcpy(buf[0], buf[1], sizeof(buf[0])); + memcpy(buf[1], buf[2], sizeof(buf[1])); + + if(length - line > 0) { + read_input(f, line*width, length, buf[2]); + } else { + memset(buf[2], 0, sizeof(buf[2])); + } + + sum += find_stars(buf[0], buf[1], buf[2]); + } + + filp_close(f, NULL); + + pr_info("%s: Answer: %d\n", MODULE_NAME, sum); + return 0; +} + +static void __exit test_exit(void) { + pr_info("%s: Module unloaded\n", MODULE_NAME); +} + +module_init(test_init); +module_exit(test_exit); diff --git a/day3/sample2 b/day3/sample2 new file mode 100644 index 0000000..b20187f --- /dev/null +++ b/day3/sample2 @@ -0,0 +1,10 @@ +467..114.. +...*...... +..35..633. +......#... +617*...... +.....+.58. +..592..... +......755. +...$.*.... +.664.598..