AoC 2024 day 5

#include <stdio.h>
#include <string.h>


int main(){
    FILE *fptr = fopen("/media/int_drive/Development/c/AoC/2024/05/input.txt", "r");
    if (fptr == NULL) { printf("Failed to open the input file"); return 1; };

    // Count number of rules and updates
    int rctr = 0, uctr = 0;
    char buf[1024];
    while(fgets(buf, sizeof(buf), fptr)){ if (strchr(buf, '|')){ ++rctr; } else if (strchr(buf, ',') ) { ++uctr; }; };
    printf("Rules: %d Updates: %d\n", rctr, uctr);
    // Reseting position in file
    rewind(fptr);
    // Creating arrays to store rules pairs
    int rarr1[rctr], rarr2[rctr];
    // Parsing rules into arrays
    int num1 = 0, num2 = 0, index = 0;
    while(fscanf(fptr, "%d|%d", &num1, &num2) == 2){ rarr1[index] = num1; rarr2[index] = num2; ++index; };
    fseek(fptr, 6*sizeof(char)*rctr, SEEK_SET); // Skipping empty line
    // Parsing updates into 2D array
    int uarr[uctr][23], uarr_bad[uctr];
    int nums[23] = {0}, bad_index = 0;
    index = 0;
    while(fscanf(fptr, "%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d",
                 &nums[0],  &nums[1],  &nums[2],  &nums[3],  &nums[4],  &nums[5],  &nums[6],  &nums[7],
                 &nums[8],  &nums[9],  &nums[10], &nums[11], &nums[12], &nums[13], &nums[14], &nums[15],
                 &nums[16], &nums[17], &nums[18], &nums[19], &nums[20], &nums[21], &nums[22]) > 0){
        for (int i = 0; i < 23; ++i){uarr[index][i] = nums[i]; };
        ++index;
        memset(nums, 0, 23 * sizeof(int)); // Reset nums values to 0
    };
    fclose(fptr);

    // Print parsing results
    // for (int i = 0; i < rctr; ++i){ printf("%d|%d\n", rarr1[i], rarr2[i]); }; putchar('\n');
    // for (int i = 0; i < uctr; ++i){ for (int j = 0; j < 23; ++j){printf("%d, ", uarr[i][j]); }; putchar('\n'); };

    // PART 1
    int mid_sum = 0;
    // Go rule one by one and check if second number is before first
    for (int i = 0; i < uctr; ++i){                   // updates row
        int good = 1;
        for (int j = 0; j < 23; ++j){                 // updates elements
            if (uarr[i][j] == 0){ break; };           // go to next row if 0
            for (int k = 0; k < rctr; ++k){           // check each rule
                if (uarr[i][j] == rarr1[k]){          // compare update number to current rule number
                    //printf("Testing rule: %d|%d on update #%d\n", rarr1[k], rarr2[k], i+1);
                    for (int l = 0; l < j; ++l){
                        if (uarr[i][l] == 0){break; };
                        if (uarr[i][l] == rarr2[k]){good = 0;  break;}; // if second rule number is before current number then report bad
                    };
                };
            };
        };
        if (good){ // Add middle number to the sum
            int last_num_index = 0;
            for (int m = 0; m < 23; ++m){ if (uarr[i][m] != 0){++last_num_index;}; };
            mid_sum += uarr[i][last_num_index / 2];
            //printf("Update #%d is good. Middle index: %d\n", i+1, last_num_index / 2);
        } else {uarr_bad[bad_index++] = i; };
    };

    printf("Sum of middle numbers of good reports: %d\n", mid_sum);
    printf("Number of bad reportes reports: %d\n", bad_index);

    // PART 2
    mid_sum = 0;
    int while_index = 0;
    // Go rule one by one and check if second number is before first
    for (int i = 0; i < bad_index; ++i){                        // updates row
        int bad = 1;
        for (int j = 0; j < 23; ++j){                           // updates elements
            if (uarr[uarr_bad[i]][j] == 0){ break; };           // go to next row if 0
            for (int k = 0; k < rctr; ++k){                     // check each rule
                if (uarr[uarr_bad[i]][j] == rarr1[k]){          // compare update number to current rule number
                    for (int l = 0; l < j; ++l){
                        if (uarr[uarr_bad[i]][l] == 0){bad = 0; break; };
                        if (uarr[uarr_bad[i]][l] == rarr2[k]){  // if second rule number is before current number just swap them
                            int temp = uarr[uarr_bad[i]][j];
                            uarr[uarr_bad[i]][j] = uarr[uarr_bad[i]][l];
                            uarr[uarr_bad[i]][l] = temp;
                            //printf("After swap: %d, %d, %d, %d, %d\n",  uarr[uarr_bad[i]][0], uarr[uarr_bad[i]][1], uarr[uarr_bad[i]][2], uarr[uarr_bad[i]][3], uarr[uarr_bad[i]][4]);
                            j = 0;                             // Go back untill fixed
                            break;
                        };
                    };
                };
            };
        };

        int last_num_index = 0;
        for (int m = 0; m < 23; ++m){ if (uarr[uarr_bad[i]][m] != 0){++last_num_index;}; };
        mid_sum += uarr[uarr_bad[i]][last_num_index / 2];
        //printf("Update #%d is good. Middle index: %d (%d) | %d %d %d %d %d \n", i+1, last_num_index / 2, uarr[uarr_bad[i]][last_num_index / 2],
        //        uarr[uarr_bad[i]][0], uarr[uarr_bad[i]][1], uarr[uarr_bad[i]][2], uarr[uarr_bad[i]][3], uarr[uarr_bad[i]][4]);

    };

    printf("Sum of middle numbers of previously bad reports: %d\n", mid_sum);

    return 0;
}