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<stdio.h>
#include<queue>
#include<algorithm>
#define INF 99999999
using namespace std;
queue <int> qy,qx,qcnt;
int dx[]={0,1,0,-1};
int dy[]={1,0,-1,0};
int n,m,x,y,cnt,nx,ny,mini,ansx,ansy;
int t[20][20],sx,sy,tx,ty,vd[20][20];
string in;
int main(){
  while(cin>>n>>m&&n){
    for(int i=0;i<n;i++){
      cin>>in;
      for(int j=0;j<(int)in.size();j++){
	if(in[j]=='A')sx=j,sy=i;
	else if(in[j]=='B')tx=j,ty=i;
	t[i][j]=(in[j]=='#');
      }
    }
    
    for(int i=0;i<20;i++)for(int j=0;j<20;j++)vd[i][j]=INF;
    vd[sy][sx]=1;
    qx.push(sx);
    qy.push(sy);
    qcnt.push(1);
    while(!qx.empty()){
      x=qx.front();qx.pop();
      y=qy.front();qy.pop();
      cnt=qcnt.front();qcnt.pop();
      for(int i=0;i<4;i++){
	nx=x+dx[i];ny=y+dy[i];
	if(!(0<=nx&&nx<m&&0<=ny&&ny<n))continue;
	if(vd[ny][nx]!=INF||t[ny][nx]==1)continue;
	vd[ny][nx]=cnt+1;
	qx.push(nx);
	qy.push(ny);
	qcnt.push(cnt+1);
      }
    }
    
    cin>>in;
    cnt=0;
    mini=INF;

    for(int I=0;I<n*m;I++){
      for(int i=0;i<(int)in.size();i++){
	cnt++;
	if(cnt>=vd[ty][tx]){
	  if(mini>cnt){
	    mini=cnt;
	    ansy=ty;
	    ansx=tx;
	  }
	}
	if(in[i]=='5')continue;
	else if(in[i]=='8'){
	  if(ty==0)continue;
	  ty--;
	}else if(in[i]=='6'){
	  if(tx==m-1)continue;
	  tx++;
	}else if(in[i]=='4'){
	  if(tx==0)continue;
	  tx--;
	}else{
	  if(ty==n-1)continue;
	  ty++;
	}
      }//for
    }//while
    if(mini==INF)cout<<"impossible"<<endl;
    else cout<<mini-1<<' '<<ansy<<' '<<ansx<<endl;
  }
  return 0;
}

C++: #import<stdio.h>
#import<queue>
int main(){
std::queue<int>q;
int w,h,f[484],i,j,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,
z=getchar(),
z-35?z>65?b=x:z>64?a=x:1:--f[x];
f[i*22]=f[i*22-~w]=-9;
getchar();
}

f[a]=t=0;
q.push(0);
for(q.push(a);a=q.front(),q.size()>1;q.pop())
if(!a)++t,q.push(0);
else for(i=4;i--;)
if(f[x=a+" 57L"[i]-54]==-1)
f[x]=t,q.push(x);

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-54+"L65676 "[p[i]-50]]>-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);
}
}

C++: #include<bits/stdc++.h>
using namespace std;
const int INF=1001001001;
typedef pair<int,int>P;
const int dx[]={-1,0,1,0,0};
const int dy[]={0,-1,0,1,0};
int H,W;
char fld[50][50];
int sy,sx,gy,gx;
int dist[50][50];
int ord[10],N;
bool ok(int y,int x){
    if(y<0||y>=H||x<0||x>=W)return false;
    return true;
}

void bfs(){
    for(int i=0;i<H;i++)for(int j=0;j<W;j++)dist[i][j]=INF;
    dist[sy][sx]=0;

    queue<P>que;que.push(P(sy,sx));

    while(que.size()){
        P p=que.front();que.pop();

        for(int i=0;i<4;i++){
            int ny=p.first+dy[i],nx=p.second+dx[i];
            if(!ok(ny,nx)||fld[ny][nx]=='#'||dist[ny][nx]!=INF)continue;
            dist[ny][nx]=dist[p.first][p.second]+1;
            que.push(P(ny,nx));
        }
    }
}

void solve(){
    for(int i=0;i<H;i++){
        cin>>fld[i];
        for(int j=0;j<W;j++){
            if(fld[i][j]=='A')sy=i,sx=j;
            if(fld[i][j]=='B')gy=i,gx=j;
        }
    }

    bfs();

    string str;cin>>str;
    N=str.size();
    for(int i=0;i<N;i++){
        switch(str[i]){
            case '5':ord[i]=4;break;
            case '8':ord[i]=1;break;
            case '4':ord[i]=0;break;
            case '2':ord[i]=3;break;
            case '6':ord[i]=2;break;
        }
    }

    for(int i=0;i<100000;i++){
        int ny=gy+dy[ord[i%N]],nx=gx+dx[ord[i%N]];
        if(ok(ny,nx)){
            gy=ny;gx=nx;
        }

        if(dist[gy][gx]<=i+1){
            cout<<i+1<<" "<<gy<<" "<<gx<<endl;
            return;
        }
    }

    cout<<"impossible"<<endl;
}

int main(){
    while(cin>>H>>W,H||W)solve();
    return 0;
}