Go: package main

import (
	"bufio"
	"fmt"
	"math"
	"os"
	"strconv"
)

func configure(scanner *bufio.Scanner) {
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 1000005), 1000005)
}
func getNextString(scanner *bufio.Scanner) string {
	scanned := scanner.Scan()
	if !scanned {
		panic("scan failed")
	}
	return scanner.Text()
}
func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}
func getNextInt64(scanner *bufio.Scanner) int64 {
	i, _ := strconv.ParseInt(getNextString(scanner), 10, 64)
	return i
}
func getNextFloat64(scanner *bufio.Scanner) float64 {
	i, _ := strconv.ParseFloat(getNextString(scanner), 64)
	return i
}
func main() {
	fp := os.Stdin
	wfp := os.Stdout
	extra := 0
	if os.Getenv("I") == "IronMan" {
		fp, _ = os.Open(os.Getenv("END_GAME"))
		extra = 100
	}
	scanner := bufio.NewScanner(fp)
	configure(scanner)
	writer := bufio.NewWriter(wfp)
	defer func() {
		r := recover()
		if r != nil {
			fmt.Fprintln(writer, r)
		}
		writer.Flush()
	}()
	solve(scanner, writer)
	for i := 0; i < extra; i++ {
		fmt.Fprintln(writer, "-----------------------------------")
		solve(scanner, writer)
	}
}
func solve(scanner *bufio.Scanner, writer *bufio.Writer) {
	dy := [4]int{-1, 0, 0, 1}
	dx := [4]int{0, -1, 1, 0}
	for {
		h := getNextInt(scanner)
		w := getNextInt(scanner)
		if h == 0 {
			break
		}
		grid := makeGrid(h, w)
		a := [2]int{}
		b := [2]int{}
		for i := 0; i < h; i++ {
			s := getNextString(scanner)
			for j := 0; j < w; j++ {
				if s[j] == '#' {
					grid[i][j] = math.MaxInt32
					continue
				}
				if s[j] == 'A' {
					a[0] = i
					a[1] = j
					continue
				}
				if s[j] == 'B' {
					b[0] = i
					b[1] = j
				}
				grid[i][j] = math.MaxInt32 - 1
			}
		}
		q := make([][2]int, 0)
		q = append(q, a)
		for len(q) > 0 {
			p := q[0]
			q = q[1:]
			for i := 0; i < 4; i++ {
				yy := p[0] + dy[i]
				xx := p[1] + dx[i]
				if yy == a[0] && xx == a[1] {
					continue
				}
				if yy < 0 || yy >= h {
					continue
				}
				if xx < 0 || xx >= w {
					continue
				}
				if grid[yy][xx] == math.MaxInt32 {
					continue
				}
				if grid[yy][xx] <= grid[p[0]][p[1]]+1 {
					continue
				}
				grid[yy][xx] = grid[p[0]][p[1]] + 1
				q = append(q, [2]int{yy, xx})
			}
		}
		move := getNextString(scanner)
		i := 0
		m := len(move)
		for {
			if i > 400 {
				fmt.Fprintln(writer, "impossible")
				break
			}
			if grid[b[0]][b[1]] <= i {
				fmt.Fprintln(writer, fmt.Sprintf("%d %d %d", i, b[0], b[1]))
				break
			}
			switch move[i%m] {
			case '8':
				if b[0] > 0 {
					b[0]--
				}
			case '6':
				if b[1]+1 < w {
					b[1]++
				}
			case '4':
				if b[1] > 0 {
					b[1]--
				}
			case '2':
				if b[0]+1 < h {
					b[0]++
				}
			}
			i++
		}
	}
}
func makeGrid(h, w int) [][]int {
	index := make([][]int, h, h)
	data := make([]int, h*w, h*w)
	for i := 0; i < h; i++ {
		index[i] = data[i*w : (i+1)*w]
	}
	return index
}

C++: #include <cstdio>
#include <cstdint>
#include <algorithm>
#include <vector>
#include <string>
#include <queue>

const size_t di[]={size_t(-1), 0, 1, 0};
const size_t dj[]={0, size_t(-1), 0, 1};
const int INF=1e9;
const size_t dti[]={0, 0, 1, 0, 0, 0, 0, 0, size_t(-1)};
const size_t dtj[]={0, 0, 0, 0, size_t(-1), 0, 1, 0, 0};

int testcase_ends() {
  size_t H, W;
  scanf("%zu %zu", &H, &W);

  if (H == 0 && W == 0)
    return 1;

  std::vector<std::string> s(H);
  size_t si=-1, sj=-1;
  size_t ti=-1, tj=-1;
  for (size_t i=0; i<H; ++i) {
    char buf[128];
    scanf("%s", buf);
    s[i] = buf;
    for (size_t j=0; j<W; ++j) {
      if (s[i][j] == 'A') {
        si = i;
        sj = j;
      } else if (s[i][j] == 'B') {
        ti = i;
        tj = j;
      }
    }
  }

  char buf[128];
  scanf("%s", buf);
  std::string t=buf;

  std::queue<std::pair<size_t, size_t>> q;
  q.emplace(si, sj);
  std::vector<std::vector<int>> dp(H, std::vector<int>(W, INF));
  dp[si][sj] = 0;
  while (!q.empty()) {
    std::pair<size_t, size_t> p=q.front();
    q.pop();
    size_t i=p.first, j=p.second;
    for (size_t k=0; k<4; ++k) {
      size_t ni=i+di[k], nj=j+dj[k];
      if (!(ni < H && nj < W)) continue;
      if (s[ni][nj] == '#') continue;
      if (dp[ni][nj] < dp[i][j] + 1) continue;
      dp[ni][nj] = dp[i][j] + 1;
      q.emplace(ni, nj);
    }
  }

  // for (size_t i=0; i<H; ++i)
  //   for (size_t j=0; j<W; ++j)
  //     if (dp[i][j] < INF)
  //       printf("%d%c", dp[i][j], j+1<W? ' ':'\n');
  //     else
  //       printf("#%c", j+1<W? ' ':'\n');

  size_t tlen=t.length();
  std::pair<size_t, size_t> res(-1, -1);
  int tt=INF;
  for (int i=0; i<1000; ++i) {
    size_t nti=ti+dti[t[i%tlen]-'0'];
    size_t ntj=tj+dtj[t[i%tlen]-'0'];
    if (nti < H) ti = nti;
    if (ntj < W) tj = ntj;
    if (dp[ti][tj] < INF) {
      if (dp[ti][tj] > i+1) continue;
      if (i+1 < tt) {
        tt = i+1;
        res = {ti, tj};
      }
    }
  }
  if (tt < INF)
    return !printf("%d %zu %zu\n", tt, res.first, res.second);
  printf("impossible\n");
  return 0;
}

int main() {
  while (!testcase_ends()) {}
}

C++: #include <iostream>
#include <vector>
#include <string>
#include <map>
#include <queue>

#define pb push_back
#define mp make_pair
#define contains(c, x) (c).find(x) != (c).end()
#define rep(i, n) for(int i = 0; i < n; ++i)

using namespace std;

int h, w;
vector<string> grid(21);
string pattern;
int g[21][21];

int dx[5] = { 0, -1, 0, 0, 1 };
int dy[5] = { 0, 0, -1, 1, 0 };

int p2i(int Time)
{
	switch (pattern[Time % pattern.size()] - '0') {
		case 5: return 0;
		case 8: return 2;
		case 6: return 4;
		case 4: return 1;
		case 2: return 3;
	}
}

int main()
{
	while (true) {
		cin >> h >> w; if (h == 0 && w == 0) break;
		rep(i, h) cin >> grid[i];
		cin >> pattern;
		
		pair<int, int> a, b;
		rep(i, h) rep(j, w)
			if (grid[i][j] == 'A') a = mp(i, j);
			else if (grid[i][j] == 'B') b = mp(i, j);

		rep(i, h) rep(j, w) g[i][j] = -1;
		queue<pair<int, int> > q;
		map<pair<int, int>, int> m;
		q.push(a);
		m[a] = 0;
		while (!q.empty()) {
			pair<int, int> t = q.front(); q.pop();
			g[t.first][t.second] = m[t];
			rep(i, 5) {
				int dr = t.first + dy[i];
				int dc = t.second + dx[i];
				pair<int, int> next = mp(dr, dc);
				if (dr < 0 || dr >= h || dc < 0 || dc >= w) continue;
				if (grid[dr][dc] == '#' || contains(m, next)) continue;
				q.push(next);
				m[next] = m[t] + 1;
			}
		}
		int T = 1;
		while (T < 10000) {
			rep(i, pattern.size()) {
				int k = p2i(T-1);
				int br = b.first + dy[k];
				int bc = b.second + dx[k];
				if (0 <= br && br < h && 0 <= bc && bc < w)
					b = mp(b.first + dy[k], b.second + dx[k]);
				br = b.first;
				bc = b.second;
				if (g[br][bc] >= 0 && g[br][bc] <= T) {
					cout << max(g[br][bc], T) << " " << br << " " << bc << endl;
					goto CONTINUE;
				}
				T++;
			}
		}
		cout << "impossible" << endl;
CONTINUE:;
	}
	return 0;
}