AdventOfCode C 2024 day 5

#include <stdio.h>

#define SIZE 1175
#define ITEM_COUNT 200
#define COL 68
#define INPUT_SIZE 15774

struct order_t {
    int val1;
    int val2;
};

typedef struct order_t Order;


void parse_inputs(FILE* file, int items[][COL], int* item_sizes, Order* rules) {
    {
        int index = 0;
        int val1;
        int val2;
        while (fscanf(file, "%d|%d", &val1, &val2) == 2) {
            Order item = { val1, val2 };
            rules[index++] = item;
        }
    }
    char buffer[COL];
    fgets(buffer, 3, file); // Just need to get an empty line
    {
        int index = 0;
        int offset = 1;
        char line[COL];
        int c;
        int val;
        while (fscanf(file, "%d", &val) == 1) {
            items[index][offset++] = val;
            if ((c = fgetc(file)) != 44) { // A comma (,)
                // End of this string of values
                item_sizes[index] = offset;
                index++;
                offset = 1;
            }
        }
    }

}


int find_order(int* val1, int* val2, Order* ordered) {
    for (size_t i = 0; i < 1175; i++) {
        Order item = *(ordered + i);
        if (item.val1 == *val1 && item.val2 == *val2) {
            // This is in the right order
            return 1;
        }
        else if (item.val1 == *val2 && item.val2 == *val1) {
            // This is in the wrong order
            return 0;
        }
    }
    //Nothing was found, so it's okay
    return 1;
}

int correct_line(int* items, int item_size, Order* ordered) {
    for (size_t i = 0; i < item_size; i++) {
        for (size_t j = i + 1; j < item_size; j++) {
            if (!find_order(items + i, items + j, ordered)) {
                return 0;
            }
        }
    }
    return 1;
}

int part_one(int items[][COL], int* item_sizes, int size, Order* ordered) {
    int total = 0;
    for (size_t i = 0; i < size; i++) {
        int* item = *(items + i);
        int size = *(item_sizes + i);
        if (size == 0) {
            break;
        }
        if (!correct_line(item, size, ordered)) {
            continue;
        }
        total += *(item + size / 2);
    }
    return total;
}
// Assume to_index < first_index
void move(int* array, int first_index, int to_index) {
    int original = *(array + first_index);
    for (size_t i = first_index; i > to_index; i--) {
        *(array + i) = *(array + i - 1);
    }
    *(array + to_index) = original;
}

void adjust_line(int* items, int item_size, Order* ordered) {
    int index = 0;
    while (index < item_size) {
        for (size_t j = index + 1; j < item_size; j++) {
            /*
                If it is in the wrong order, put the second one just before the first and reduce index by one
             */
            if (find_order(items + index, items + j, ordered)) {
                continue;
            }
            move(items, j, index);
            index--;
            break;
        }
        index++;
    }
}

int part_two(int items[][COL], int* item_sizes, int size, Order* ordered) {
    /*
    If it is in the wrong order, put the second one just before the first and reduce index by one
     */
    int total = 0;
    for (size_t i = 0; i < size; i++) {
        int* item = *(items + i);
        int size = *(item_sizes + i);
        if (size == 0) {
            break;
        }
        if (correct_line(item, size, ordered)) {
            continue;
        }
        adjust_line(item, size, ordered);
        total += *(item + size / 2);
    }
    return total;
}
int main() {
    FILE* ptr = fopen("2024-5.txt", "r");
    Order rules[SIZE];
    int items[ITEM_COUNT][COL];
    int sizes[ITEM_COUNT];
    parse_inputs(ptr, items, sizes, rules);
    printf("Part one: %d\n", part_one(items, sizes, ITEM_COUNT, rules));
    printf("Part two: %d\n", part_two(items, sizes, ITEM_COUNT, rules));
}