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 <string.h>
#include <list>
#include <algorithm>

using namespace std;

typedef struct {
	int x, y;
} Vector;

typedef struct {
	int x, y;
	int step;
} DATA;

unsigned int data[16 + 2][16 + 2];
char map[16 + 2][16 + 2];

int change(char move[], Vector mv[])
{
	int i = 0;
	while (move[i] != '\0'){
		mv[i].x = mv[i].y = 0;
		switch (move[i]){
		  case '5':
		  	break;
		  case '8':
		  	mv[i].y = -1;
			break;
		  case '6':
		  	mv[i].x = 1;
			break;
		  case '4':
		  	mv[i].x = -1;
			break;
		  case '2':
		  	mv[i].y = 1;
			break;
		}
		i++;
	}
	return (i);
}

unsigned int move_sml(int gx, int gy, Vector mv[], int move_count, int* ans_x, int* ans_y)
{
	unsigned int ret = 0xffffffff;
	for (unsigned int i = 0; i < 1000000; i++){
		int mx = mv[i % move_count].x;
		int my = mv[i % move_count].y;
		
		if (data[gx][gy] <= i && ret > i){
			ret = max(data[gx][gy], i);
			*ans_x = gx;
			*ans_y = gy;
		}
		
		if (map[gx + mx][gy + my] != -1){
			gx += mx;
			gy += my;
		}
	}
	
	return (ret);
}

int move_short_root(int sx, int sy)
{
	list<DATA> lst;
	DATA add;
	
	data[sx][sy] = 0;
	
	add.x = sx + 1;
	add.y = sy;
	add.step = 1;
	lst.push_back(add);
	add.x = sx - 1;
	add.y = sy;
	add.step = 1;
	lst.push_back(add);
	add.x = sx;
	add.y = sy + 1;
	add.step = 1;
	lst.push_back(add);
	add.x = sx;
	add.y = sy - 1;
	add.step = 1;
	lst.push_back(add);
	
	while (!lst.empty()){
		if (map[lst.front().x][lst.front().y] != -1 && map[lst.front().x][lst.front().y] != '#' && data[lst.front().x][lst.front().y] > lst.front().step){
			data[lst.front().x][lst.front().y] = lst.front().step;
			add.x = lst.front().x + 1;
			add.y = lst.front().y;
			add.step = lst.front().step + 1;
			lst.push_back(add);
			add.x = lst.front().x - 1;
			add.y = lst.front().y;
			lst.push_back(add);
			add.x = lst.front().x;
			add.y = lst.front().y + 1;
			lst.push_back(add);
			add.x = lst.front().x;
			add.y = lst.front().y - 1;
			lst.push_back(add);
		}
		lst.pop_front();
	}
	
	return (0);
}

int main(void)
{
	int hight, width;
	int ans_x, ans_y;
	int sx, sy, gx, gy;
	char move[11];
	Vector mv[10];
	int move_count;
	unsigned int ans;
	
	while (1){
		memset(data, 0xff, (18 * 18) * sizeof(int));
		cin >> hight >> width;
		if (hight == 0 && width == 0)break;
		for (int y = 0; y < hight + 2; y++){
			char str[16 + 1];
			if (y == 0 || y == hight + 1){
				for (int x = 0; x < width + 2; x++){
					map[x][y] = -1;
				}
			}
			else {
				cin >> str;
				map[0][y] = map[width + 1][y] = -1;
				for (int x = 0; x < width; x++){
					if (str[x] == 'A'){
						sx = x + 1;
						sy = y;
					}
					if (str[x] == 'B'){
						gx = x + 1;
						gy = y;
					}
					map[x + 1][y] = str[x];
				}
			}
		}
		cin >> move;
		
		move_count = change(move, mv);
		
		move_short_root(sx, sy);
		
		ans = move_sml(gx, gy, mv, move_count, &ans_x, &ans_y);
		
		if (ans == 0xffffffff){
			cout << "impossible" << endl;
		}
		else {
			cout << ans << ' ' << ans_y - 1 << ' ' << ans_x - 1 << endl;
		}
		
	}
	
	return (0);
}

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>1000){
                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));
        }
    }
}