thomas_2023/day_3/aoc2023p1.c

#define BREAK_MY_SHIT

#ifdef BREAK_MY_SHIT
#include <linux/module.h>     /* Needed by all modules */
#include <linux/kernel.h>     /* Needed for KERN_INFO */
#include <linux/init.h>       /* Needed for the macros */
#include <linux/ctype.h>

MODULE_LICENSE("Proprietary and Confidential; All Rights Reserved");
MODULE_AUTHOR("Urmomlel");
MODULE_DESCRIPTION("Vanguard Anticheat");
MODULE_VERSION("-6.9");
#else
#include <stdio.h>
#include <ctype.h>

#define __init
#define __exit
#define KERN_INFO
#define printk printf
#endif

#include "input.h"
// #include "hint.h"

// Skip over all non numeric characters
// Return index of first numeric character found
int find_int(const char *line) {
    int i = 0;
    for(; *line; ++line) {
        if(isdigit(*line))
            return i;
        i++;
    }

    return -1;
}

// Convert string to int, return digits consumed
int get_int(const char *line, int *num_out) {
    int i = 0;
    *num_out = 0;

    // Handle the edge case that will never happen (tm)
    if(!isdigit(*line))
        return -1;

    for(; *line; ++line,++i) {
        if(!isdigit(*line))
            break;

        *num_out *= 10;
        *num_out += *line - 0x30;
    }

    return i;
}

// Search around an int for "components"
// x    x   x x x  x   x
// x [start n n n end] x  <-- y
// x    x   x x x  x   x
// x is searched area
// [start n end] is where the "part number" is
// Return 1 if found
int search_component(int y, int start, int end) {
    int left = start - 1;
    int right = end + 1;
    int top = y - 1;
    int bottom = y + 1;

    // Spot check the immediate left and right characters
    if(left >= 0 && input[y][left] != '.') return 1;
    if(right < input_width && input[y][right] != '.') return 1;

    // Check top row
    // We can clamp left and right now
    if(left < 0) left = 0;
    if(right >= input_width) right = input_width - 1;

    // Check top row if it is valid
    if(top > 0) {
        for(int i = left; i <= right; i++)
            if(input[top][i] != '.') return 1;
    }
    // Check bottom row if it is valid
    if(bottom < input_height) {
        for(int i = left; i <= right; i++)
            if(input[bottom][i] != '.') return 1;
    }

    return 0;
}

static int __init aoc_start(void) {
    printk(KERN_INFO "aoc_start\n");

    int part_number_count = 0;

    for(int y = 0; y < input_height; y++) {
        const char *line = input[y];
        int head = 0;
        while(1) {
            // Find a number
            printk("line[head] %s\n", &line[head]);
            int skipped = find_int(&line[head]);
            printk("skipped %d\n", skipped);
            if(skipped == -1) break;
            head += skipped;
            // Save start index so we can pass it to search later
            int start = head;

            // Read the int
            int number = 0;
            printk("line[start] %s\n", &line[head]);
            int number_num_chars = get_int(&line[head], &number);
            if(number_num_chars < 0) {
                printk("Bad shit happened\n");
                return -1;
            }
            head += number_num_chars;

            printk("number %d\n", number);
            printk("n_number %d\n", number_num_chars);

            printk("context:\n");
            if(y-1 > 0)
                printk("%s\n", input[y-1]);
            printk("%s\n", input[y]);
            if(y+1 < input_height)
                printk("%s\n", input[y+1]);
            int valid = search_component(y, start, head - 1);
            printk("valid %d\n", valid);

            if(valid)
                part_number_count += number;
        }

        printk("\n");
    }

    printk("Part number count: %d\n", part_number_count);

    return 0;
}

static void __exit aoc_end(void) {
    printk(KERN_INFO "aoc_end\n");
}

#ifdef BREAK_MY_SHIT
module_init(aoc_start);
module_exit(aoc_end);
#else
int main() {
    aoc_start();
    aoc_end();
}
#endif