オフラインどう書く第12回参考問題 (C 力技版)

なんの工夫もない力技版です。

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

#define NDIRS 4

const char *str = "?ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
                  "abcdefghijklmnopqrstuvwxyz" \
                  "01234567";
int dirs[NDIRS][60] = {
    {
         1,  2,  3,  4,  5,  6,  7,  8,  9, 10, -1, 12, 13, 14, 15, 16,
        17, 18, 19, 20, 21, -1, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32,
        -1, 34, 35, -1, 37, 38, -1, 40, 41, -1, 43, 44, -1, 46, 47, -1,
        49, 50, -1, 52, 53, -1, 55, 56, -1, 58, 59, -1
    },
    {
        11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
        27, 28, 29, 30, 31, 32, 33, 34, 35, -1, -1, -1, -1, -1, 59, 58,
        57, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
        51, 52, 53, 54, 55, 56, 57, 58, 59, 32, 31, 30
    },
    {
        -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, 11, 12, 13, 14,
        15, 16, 17, 18, 19, 20, -1, 22, 23, 24, 25, 26, 27, 28, 29, 30,
        31, -1, 33, 34, -1, 36, 37, -1, 39, 40, -1, 42, 43, -1, 45, 46,
        -1, 48, 49, -1, 51, 52, -1, 54, 55, -1, 57, 58
    },
    {
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  0,  1,  2,  3,  4,
         5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
        21, 22, 23, 24, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44,
        45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56
    }
};


void solve(char *r, const char *s)
{
    int next;
    int step;
    int dir;
    int pos;
    int i;

    step = 0;
    dir = 0;
    pos = 0;
    *r++ = str[pos + 1];
    for (; *s != '\0'; s++) {
        if (*s == 'R')
            dir = (dir + 1) % NDIRS;
        else if (*s == 'L')
            dir = (dir - 1 + NDIRS) % NDIRS;
        else if (*s >= '0' && *s <= '9')
            step = *s - '0';
        else if (*s >= 'a' && *s <= 'f')
            step = *s - 'a' + 10;
        for (; step > 0; step--) {
            next = dirs[dir][pos];
            *r++ = str[next + 1];
            if (next == -1)
                goto end;
            for (i = 0; i < NDIRS; i++) {
                if (dirs[i][next] == pos) {
                    dir = (i + 2) % NDIRS;
                    break;
                }
            }
            pos = next;
        }
    }
end:
    *r = '\0';
}

void test(const char *in, const char *out)
{
    char r[80];

    solve(r, in);

    printf("%s -> %s(%s) %s\n", in, r, out,
        strcmp(r, out) == 0 ? "ok" : "ng");
}

int main(void)
{
/*0*/ test( "2RcL3LL22", "ABCNYjmpsvy147edcbcdef" );
...snip...
    return 0;
}