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 <vector>
#include <queue>
#include <algorithm>
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
#define mp make_pair
int w,h;
char data[20][20];
bool able[20][20];
vector<int>  step[20][20];
string L;
int mi,miy,mix;
vector<int>::iterator it;

queue< pair<pair<int,int>,int> > que;

void go(int y,int x,int dp){
	if(y-1>=0 && data[y-1][x]!='#'){
		que.push(mp(mp(y-1,x),dp));
		data[y-1][x]='#';
	}
	if(y+1<h  && data[y+1][x]!='#'){
		que.push(mp(mp(y+1,x),dp));
		data[y+1][x]='#';
	}
	if(x-1>=0 && data[y][x-1]!='#'){
		que.push(mp(mp(y,x-1),dp));
		data[y][x-1]='#';
	}
	if(x+1<w  && data[y][x+1]!='#'){
		que.push(mp(mp(y,x+1),dp));
		data[y][x+1]='#';
	}
}
void bfs(int y,int x,int dp){
	int wait;
	go(y,x,dp+1);

	if(able[y][x]){
		it = lower_bound(step[y][x].begin(),step[y][x].end(),dp);
		if(it == step[y][x].end())return;
		wait = *it-dp;
		if(dp+wait<mi){
			mi = dp+wait;
			miy = y;
			mix = x;
		}
	}

	while(!que.empty()){
		y = que.front().first.first;
		x = que.front().first.second;
		dp = que.front().second;
		que.pop();
		if(able[y][x]){
			it = lower_bound(step[y][x].begin(),step[y][x].end(),dp);
			if(it == step[y][x].end())return;
			wait = *it-dp;
			if(dp+wait<mi){
				mi = dp+wait;
				miy = y;
				mix = x;
			}
		}
		go(y,x,dp+1);
	}
}

int main(){
	int sx,sy,gy,gx;
	while(cin >> h >> w , h){
		mi = (1<<21);
		bool flag = true;
		rep(i,20)rep(j,20){
			able[i][j]=false;
			step[i][j].clear();
		}

		rep(i,h)rep(j,w){
			cin >> data[i][j];
			if(data[i][j]=='A'){
				sy = i;
				sx = j;
			}
			if(data[i][j]=='B'){
				gy = i;
				gx = j;
			}
		}
		cin >> L;
		int r = 0;
		for(int k=0;k<40000;k++){
			for(int i=0;i<L.size();i++){
				able[gy][gx] = true;
				step[gy][gx].push_back(r);
				switch(L[i]){
				case '5':
					break;
				case '8':
					if(gy-1>=0)gy-=1;
					break;
				case '2':
					if(gy+1<h)gy+=1;
					break;
				case '4':
					if(gx-1>=0)gx-=1;
					break;
				case '6':
					if(gx+1<w)gx+=1;
					break;
				}
				r++;
			}
		}
		bfs(sy,sx,0);
		if(mi != (1<<21) ){
			cout << mi << " " << miy << " " << mix << endl;
		}else{
			cout << "impossible" << endl;
		}
	}
}

C++: #include<stdio.h>
#include<queue>
int main(){
	std::queue<int>q;
	int w,h,f[484],i,j,d[]={22,0,-1,0,1,0,-22},a,b,t,x,z;
	char p[15];
	for(;scanf("%d%d ",&h,&w),h;){
		for(j=0;j<w+2;j++)f[j]=f[j-~h*22]=-9;
		for(i=1;i<=h;i++){
			for(j=1;j<=w;j++){
				f[x=i*22+j]=-1;
				switch(getchar()){
					case'#':--f[x];break;
					case'A':a=x;break;
					case'B':b=x;break;
				}
			}
			f[i*22]=f[i*22-~w]=-9;
			getchar();
		}
		
		f[a]=t=0;
		q.push(0);
		for(q.push(a);q.size()>1;){
			a=q.front();
			q.pop();
			if(a){
				for(i=0;i<7;i+=2)
					if(f[x=a+d[i]]==-1)
						f[x]=t,q.push(x);}
			else
				++t,q.push(0);
		}
		q.pop();
		scanf("%s",p);
		for(a=t=0;!a;){
			x=b;
			z=0;
			for(i=0;!a&&p[i];i++){
				t++;
				f[j=b+d[p[i]-'2']]>-3?b=j:0;
				f[b]>=0&&t>=f[b]?a=b:0;
				f[b]>=0&&++z;
			}
			!z&!a&!p[i]&b==x&f[b]<0&&--a;
		}
		printf(a<0?"impossible\n":"%d %d %d\n",t,a/22-1,a%22-1);
	}
}