/* === aoc202406 =======================================================
   Hmmm, I've done something like this already this year... on day 4
   I need rcmap() moved to aocutils ... done; now it's called `linearize2d`
Part Two: brute force? It likely is faster than coming up with an algo
   Let's go: save map, for every available position put in an obstacle,
   loop around until some place is visited 4? times or area is exited
TODO remove linearize2d
===================================================================== */

static bool validpos(unsigned s, int r, int c) {
    if (r < 0) return false;
    if (c < 0) return false;
    if ((unsigned)r >= s - 1) return false;
    if ((unsigned)c >= s - 1) return false;

        accumsum += accum;
    } while ((line = strtok(NULL, "\n")) != NULL);
    printf("The sum of middle update numbers is {%u}.\n", accumsum);
    printf("The sum of middle update numbers for newly ordered updates is {%u}.\n", accumsum2);
}

/* === aoc202404 =======================================================
TODO remove linearize2d
===================================================================== */

static bool masat(char *data, unsigned size, unsigned row, unsigned col, int drow, int dcol) {
    int maxrow = (int)row + 3*drow;
    int maxcol = (int)col + 3*dcol;
    if ((0 <= maxrow) && (maxrow < (int)size) && (0 <= maxcol) && (maxcol < (int)size)) {
        if (data[linearize2d(size+1, (unsigned)((int)row + drow), (unsigned)((int)col + dcol))] != 'M') return false;

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include "aocutils.h"

bool TGvalid(struct TextGrid *tg, unsigned row, unsigned col) {
    if (row >= tg->rows) return false;
    if (col >= tg->cols) return false;
    return true;
}
char *TGcharptr(struct TextGrid *tg, unsigned row, unsigned col) {
    if (!TGvalid(tg, row, col)) return NULL;
    return tg->data + (row * tg->cols) + col;
}

// TODO: rewrite this shit
size_t linearize2d(unsigned width, unsigned row, unsigned col) {
    return (row * width) + col;
}

size_t text2array(unsigned **dst, const char *r) {
    unsigned *a = malloc(512 * sizeof *a);
    size_t na = 0, sa = 512;

#ifndef AOCUTILS_H_INCLUDED
#define AOCUTILS_H_INCLUDED

struct TextGrid {
    unsigned rows, cols;
    char *data; // may have '\n' at end of rows
};

bool TGvalid(struct TextGrid *tg, unsigned row, unsigned col);
char *TGcharptr(struct TextGrid *tg, unsigned row, unsigned col);

size_t linearize2d(unsigned width, unsigned row, unsigned col); // TODO
size_t text2array(unsigned **dst, const char *txt);
size_t slurp(char **dst, const char *filename);
unsigned distance(unsigned a, unsigned b);
unsigned max3u(unsigned a, unsigned b, unsigned c);
unsigned min3u(unsigned a, unsigned b, unsigned c);

#endif

............
........0...
.....0......
.......0....
....0.......
......A.....
............
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........A...
.........A..
............
............

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

#include "aocutils.h"

int main(void) {
    char *input = NULL;
    size_t ilen = slurp(&input, "test.txt");

    struct TextGrid tg;
    tg.data = input;
    tg.cols = strchr(input, '\n') - input + 1;
    tg.rows = tg.cols - 1; // rows includes the '\n'

    if (*TGcharptr(&tg, 11, 11) == '.') puts("1");
    if (TGcharptr(&tg, 12, 11) == NULL) puts("2");
    if (TGcharptr(&tg, 11, 12) == NULL) puts("3");
    if (*TGcharptr(&tg, 11, 12) == '\n') puts("33");
    if (TGcharptr(&tg, -1, -2) == NULL) puts("4");

    for (int k = 0; k < 12; k++) {
        *TGcharptr(&tg, k, k) = '#';
    }
    printf("\n\n%s\n", tg.data);
}