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 <iostream>
#include <algorithm>
#include <string>
#include <queue>

using namespace std;

struct St{
  int ax, ay, bx, by, cst;
  St() {}
  St(int _ay, int _ax, int _by, int _bx, int _cst): ay(_ay), ax(_ax), by(_by), bx(_bx), cst(_cst) {}

  bool check(){
    return (ax == bx && ay == by);
  }

  void print(){
    cout << cst << " " << by << " " << bx << endl;
    return ;
  }
};

int p_n, w, h, pat[10];
char a[21][21];
bool vis[20][20][20][20][10];
int xdir[5] = {0, 1, 0, -1, 0}, ydir[5] = {-1, 0, 1, 0, 0};

bool bfs(St stt)
{
  queue<St> que;
  que.push(stt);

  while(!que.empty()){
    St st = que.front();
    que.pop();

    if(st.check()){
      st.print();
      return false;
    }
    int p = st.cst%p_n;
    int nby = st.by+ydir[pat[p]], nbx = st.bx+xdir[pat[p]];

    if(0 > nby || nby >= h || 0 > nbx || nbx >= w){
      nby = st.by; nbx = st.bx;
    }

    for(int i = 0; i < 5; ++i){
      int dy = st.ay+ydir[i], dx = st.ax+xdir[i];
      if(!(0 <= dy && dy < h && 0 <= dx && dx < w && a[dy][dx] == '.')){
	dy = st.ay; dx = st.ax;
      }

      if(vis[dy][dx][nby][nbx][p]){
	vis[dy][dx][nby][nbx][p] = false;
	que.push(St(dy, dx, nby, nbx, st.cst+1));
      }
    }
  }

  return true;
}

int main()
{
  int s, t, u, v;
  string str;

  while(cin>>h>>w && h+w){
    fill(&vis[0][0][0][0][0], &vis[20][0][0][0][0], true);

    for(int i = 0; i < h; ++i)
      for(int j = 0; j < w; ++j){
	cin >> a[i][j];
	if(a[i][j] == 'A'){
	  s = i; t = j;
	  a[i][j] = '.';
	} else if(a[i][j] == 'B'){
	  u = i; v = j;
	  a[i][j] = '.';
	}
      }
    cin >> str;
    p_n = str.size();

    for(int i = 0; i < p_n; ++i){
      if(str[i] == '8') pat[i] = 0;
      else if(str[i] == '2') pat[i] = 2;
      else if(str[i] == '6') pat[i] = 1;
      else if(str[i] == '4') pat[i] = 3;
      else if(str[i] == '5') pat[i] = 4;
    }

    if(bfs(St(s, t, u, v, 0))) cout << "impossible" << endl;
  }

  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

typedef long long ll;
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define each(itr,c) for(__typeof(c.begin()) itr=c.begin(); itr!=c.end(); ++itr)
#define all(x) (x).begin(),(x).end()
#define pb push_back
#define fi first
#define se second

struct Place{ int x,y; };
struct State
{
    Place h,g;
    int p;
};

const int INF=123456789;
int z[20][20][20][20][10];
inline void init()
{
    rep(a,20)rep(b,20)rep(c,20)rep(d,20)rep(e,10) z[a][b][c][d][e]=INF;
}

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

int main()
{
    int h,w;
    while(cin >>h >>w,h)
    {
        vector<string> s(h);
        rep(i,h) cin >>s[i];

        string pattern;
        cin >>pattern;
        int P=pattern.size();
        vector<int> pat(P);
        rep(i,P)
        {
            if(pattern[i]=='6') pat[i]=0;
            else if(pattern[i]=='4') pat[i]=1;
            else if(pattern[i]=='2') pat[i]=2;
            else if(pattern[i]=='8') pat[i]=3;
            else if(pattern[i]=='5') pat[i]=4;
        }

        Place a,b;
        rep(i,h)rep(j,w)
        {
            if(s[i][j]=='A') a=Place{j,i};
            if(s[i][j]=='B') b=Place{j,i};
        }

        init();
        z[a.y][a.x][b.y][b.x][0]=0;
        queue<State> que;
        que.push(State{a,b,0});
        #define IN(x,y) (0<=x && x<w && 0<=y && y<h)
        while(!que.empty())
        {
            State now=que.front(); que.pop();
            a=now.h;
            b=now.g;
            int idx=now.p;
            int nowZ=z[a.y][a.x][b.y][b.x][idx];

            // ???????????????
            int nbx=b.x+dx[pat[idx]], nby=b.y+dy[pat[idx]];
            if(!IN(nbx,nby))
            {
                nbx=b.x;
                nby=b.y;
            }
            Place nb=Place{nbx,nby};
            int nidx=(idx+1)%P;

            // ????????????
            rep(i,5)
            {
                int nax=a.x+dx[i], nay=a.y+dy[i];
                if(IN(nax,nay) && s[nay][nax]!='#' && z[nay][nax][nby][nbx][nidx] > nowZ+1)
                {
                    z[nay][nax][nby][nbx][nidx] = nowZ+1;
                    Place na=Place{nax,nay};
                    que.push(State{na,nb,nidx});
                }
            }
        }

        int ans=INF,ax=-1,ay=-1;
        rep(i,h)rep(j,w)rep(k,P)
        {
            if(ans>z[i][j][i][j][k])
            {
                ans=z[i][j][i][j][k];
                ax=j;
                ay=i;
            }
        }

        if(ans==INF) printf("impossible\n");
        else printf("%d %d %d\n", ans,ay,ax);
    }
    return 0;
}