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++: #define _USE_MATH_DEFINES
#define INF 0x3f3f3f3f
#include <iostream>
#include <sstream>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <queue>
#include <stack>
#include <limits>
#include <map>
#include <string>
#include <cstring>
#include <set>
#include <deque>
#include <bitset>
#include <list>
 
using namespace std;
 
typedef long long ll;
typedef pair <int,int> P;
 
static const double EPS = 1e-8;

static const int tx[] = {0,1,0,-1};
static const int ty[] = {-1,0,1,0};

int H,W;
char stage[20][20];
string ghost;
bool visited[20][20][20][20][10];
int gTime = 0;
int rx,ry;

class State {
public:
  int _sx,_sy,_gx,_gy,_time;
  State(int sx,int sy,int gx,int gy,int time) : 
    _sx(sx),_sy(sy),_gx(gx),_gy(gy),_time(time) {}
  bool operator<(const State &s) const {
    return _time < s._time;
  }
  bool operator>(const State &s) const {
    return _time > s._time;
  }
};

void bfs(int sx,int sy,int gx,int gy){
  State init(sx,sy,gx,gy,0);
  
  priority_queue<State,vector<State>,greater<State> > que;
  que.push(init);

  while(!que.empty()){
    State s = que.top();
    que.pop();

    int pattern_i = s._time % ghost.size();
    if(ghost[pattern_i] == '5'){
      //nothing to do
    }
    else if(ghost[pattern_i] == '8' && s._gy - 1 >= 0){
      s._gy--;
    }
    else if(ghost[pattern_i] == '6' && s._gx + 1 < W){
      s._gx++;
    }
    else if(ghost[pattern_i] == '4' && s._gx - 1 >= 0){
      s._gx--;
    }
    else if(ghost[pattern_i] == '2' && s._gy + 1 < H){
      s._gy++;
    }

    if(!visited[s._sx][s._sy][s._gx][s._gy][pattern_i]){
      visited[s._sx][s._sy][s._gx][s._gy][pattern_i] = true;
      if(s._sx == s._gx && s._sy == s._gy && gTime > s._time){
        gTime = s._time;
        rx = s._gx;
        ry = s._gy;
        return;
      }
      que.push(State(sx,sy,s._gx,s._gy,s._time+1));
    }
    for(int i = 0; i < 4; i++){
      int dx = tx[i] + s._sx;
      int dy = ty[i] + s._sy;
      if(dx < 0 || dx >= W || dy < 0 || dy >= H) continue;
         if(stage[dy][dx] == '#') continue;
         if(visited[dx][dy][s._gx][s._gy][pattern_i]) continue;
         
         visited[dx][dy][s._gx][s._gy][pattern_i] = true;
         if(dx == s._gx && dy == s._gy && gTime > s._time){
           gTime = s._time;
           rx = s._gx;
           ry = s._gy;
           return;
         }
         que.push(State(dx,dy,s._gx,s._gy,s._time+1));
    }
  }
}

int main(){
  while(~scanf("%d %d",&H,&W)){
    if(H == 0 && W == 0) break;

    int sx,sy,gx,gy;
    memset(visited,false,sizeof(visited));
    gTime = INF;

    for(int y = 0; y < H; y++){
      char line[32];
      scanf("%s",line);
      for(int x = 0; x < W; x++){
        stage[y][x] = line[x];
        if(stage[y][x] == 'A'){
          sx = x;
          sy = y;
        }
        if(stage[y][x] == 'B'){
          gx = x;
          gy = y;
        }
      }
    }
    cin >> ghost;
    rx = -1;
    ry = -1;
    bfs(sx,sy,gx,gy);
    
    if(gTime == INF){
      printf("impossible\n");
    }
    else{
      printf("%d %d %d\n",gTime + 1,ry,rx);
    }
  }
}

C++: #include<iostream>
#include<queue>
using namespace std;
typedef pair<pair<int,int>,int> pa;
#define ff first.first
#define fs first.second

int h,w,sx,sy,gx,gy;
int dx[4]={1,0,-1,0};
int dy[4]={0,-1,0,1};
int co[21][21];
char ma[21][21];
bool visited[21][21];
string pat;
int m = 999999;

int main(){
    while(cin>>h>>w,h){
        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                co[i][j]=m;
                cin>>ma[i][j];
                if(ma[i][j]=='A')
                    sx=j,sy=i;
                else if(ma[i][j]=='B')
                    gx=j,gy=i;
            }
        }
        queue<pa>q;
        q.push(make_pair(make_pair(sx, sy), 0));
        while(q.size()){
            pa p = q.front();
            q.pop();
            if(co[p.fs][p.ff]!=m)
                continue;
            co[p.fs][p.ff]=p.second;
            for(int i=0;i<4;i++){
                int nx=p.ff+dx[i];
                int ny=p.fs+dy[i];
                if(nx>=0&&nx<w&&ny>=0&ny<h&&ma[ny][nx]!='#'&&co[ny][nx]==m)
                    q.push(make_pair(make_pair(nx, ny), p.second+1));
            }
        }
        cin>>pat;
        for(int j=0,go=0;;j++,go++){
            int i=j%pat.length();
            if(co[gy][gx]<=go){
                cout<<go<<" "<<gy<<" "<<gx<<endl;
                break;
            }
            if(go>700){
                cout<<"impossible"<<endl;
                break;
            }
            if(pat[i]=='8')
                gy--;
            else if(pat[i]=='6')
                gx++;
            else if(pat[i]=='4')
                gx--;
            else if(pat[i]=='2')
                gy++;
            gy=max(0,min(h-1,gy));
            gx=max(0,min(w-1,gx));
        }
    }
}