AoC 2024 day 6

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

enum directions {UP, RIGHT, DOWN, LEFT};

int main(){
    FILE *fptr = fopen("/media/int_drive/Development/c/AoC/2024/06/input.txt", "r");
    if (fptr == NULL) { printf("Failed to open the input file"); return 1; };

    // Count number of lines and number of columns
    int rctr = 0, cctr = 0;
    char buf[1024];
    while(fgets(buf, sizeof(buf), fptr)){ ++rctr; if(cctr == 0){cctr = strlen(buf)-1; }; };
    printf("Field size: %dx%d (rows x columns)\n", rctr, cctr);
    rewind(fptr);
    // Copy field into 2D array
    char field[rctr][cctr];
    int row = 0, col = 0, x = -1, y =-1;
    while(!feof(fptr)) {
        char ch = fgetc(fptr);
        switch(ch) {
            case '\n': ++row; col = 0; break;
            case '^': x = row, y = col; field[row][col++] = '.'; break;
            default: field[row][col++] = ch; break;
        };
    };
    fclose(fptr);

    printf("Starting coordinates: %dx%d (row x column)\n", x, y);
    //for (int i = 0; i < rctr; ++i){ for (int j = 0; j < cctr; ++j) { putchar(field[i][j]); }; putchar('\n'); };
    // PART 1
    // Moving guard and counting steps
    int direction = UP, positions = 0, wctr = 0;
    int p1x = x, p1y = y;
    while(1){
        if (p1x < 0 || p1y < 0 || p1x >= rctr || p1y >= cctr){break; };
        if (field[p1x][p1y] == '.') { ++positions; field[p1x][p1y] = 'X'; };
        switch(direction){
            case UP:    { (field[p1x-1][p1y] == '#') ? (direction = RIGHT) : (--p1x); break; };
            case RIGHT: { (field[p1x][p1y+1] == '#') ? (direction = DOWN)  : (++p1y); break; };
            case DOWN:  { (field[p1x+1][p1y] == '#') ? (direction = LEFT)  : (++p1x); break; };
            case LEFT:  { (field[p1x][p1y-1] == '#') ? (direction = UP)    : (--p1y); break; };
        };

        if (++wctr > 10000){printf("Breaking infinite while loop!."); break;};
    };

    printf("Total number of distinct positions: %d (number of loops: %d)\n", positions, wctr);

    // PART 2
    positions = 0;
    int p2x = x, p2y = y;
    for (int row = 0; row < rctr; ++row){ for (int col = 0; col < cctr; ++col){ if (field[row][col] == 'X'){ field[row][col] = '.'; }; }; }; // Removing 'X' from part 1
    //for (int i = 0; i < rctr; ++i){ for (int j = 0; j < cctr; ++j) { putchar(field[i][j]); }; putchar('\n'); };

    for (int row = 0; row < rctr; ++row){ for (int col = 0; col < cctr; ++col){ // Looping through rows and cols
            if(row == x && col == y) { continue; };
            if(field[row][col] == '.'){ field[row][col] = '#'; } else { continue; }; // Change cell to '#' only if it is possible
            wctr = 0, p2x = x, p2y = y, direction = UP;
            while(1){
                if (p2x < 0 || p2y < 0 || p2x >= rctr || p2y >= cctr){ break; };
                switch(direction){
                    case UP:    { (field[p2x-1][p2y] == '#') ? (direction = RIGHT) : (--p2x); break; };
                    case RIGHT: { (field[p2x][p2y+1] == '#') ? (direction = DOWN)  : (++p2y); break; };
                    case DOWN:  { (field[p2x+1][p2y] == '#') ? (direction = LEFT)  : (++p2x); break; };
                    case LEFT:  { (field[p2x][p2y-1] == '#') ? (direction = UP)    : (--p2y); break; };
                };

                if (++wctr > 10000){ ++positions; break; };
            };

            field[row][col] = '.'; // Removing added obstruction for next loop
    }; };

    printf("Total number of obstruction positions: %d\n", positions);

    return 0;
}