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 <map>
#include <string>
#include <string.h>
using namespace std;

typedef pair<int,int> P;//y,x

const int dx[] = {1,0,-1,0,0};//東、南、西、北、無
const int dy[] = {0,1,0,-1,0};

int gdx[10];
int gdy[10];
int field[21][21];

int cost[21][21][21][21][10];

struct S
{
	P m;
	P g;
	int gp;
	S(P m_,P g_,int gp_):m(m_),g(g_),gp(gp_){}
};

int main(void)
{
	gdx[5]=0;gdx[8]=0;gdx[6]=1;gdx[4]=-1;gdx[2]=0;
	gdy[5]=0;gdy[8]=-1;gdy[6]=0;gdy[4]=0;gdy[2]=1;
	while(1){
		memset(cost,-1,sizeof(cost));
		memset(field,0,sizeof(field));
		P ms,gs;
		vector<int> gp;
		int W,H;
		cin >> H >> W;
		if(H==0 && W==0)
			return 0;
		for(int y=1;y<=H;++y){
			string in;
			cin >> in;
			for(int x=1;x<=W;++x){
				field[y][x] = in[x-1];
				if(field[y][x] == 'A'){
					field[y][x] = '.';
					ms.first = y;
					ms.second = x;
				}
				if(field[y][x] == 'B'){
					field[y][x] = '.';
					gs.first = y;
					gs.second = x;
				}
			}
		}
		string in;
		cin >> in;
		for(int i=0;i<in.size();++i){
			gp.push_back(in[i]-'0');
		}
		////////////////////////////////////////
		queue<S> q;
		q.push(S(ms,gs,0));
		int turn=0;
		P g(-1,-1);
		int gt=-1;
		bool isGoal=false;
		cost[ms.first][ms.second][gs.first][gs.second][gp.size()-1] = 0;
		while(!q.empty()){
			int size=q.size();
			for(int aaa=0;aaa<size;++aaa){
				S s = q.front(); q.pop();
				P gn = P(s.g.first+gdy[gp[turn]],s.g.second+gdx[gp[turn]]);
				if(field[gn.first][gn.second] == 0)
					gn = s.g;
				for(int i=0;i<5;++i){
					P mn = P(s.m.first+dy[i],s.m.second+dx[i]);
					if(cost[mn.first][mn.second][gn.first][gn.second][turn] == -1 && field[mn.first][mn.second] == '.'){
						cost[mn.first][mn.second][gn.first][gn.second][turn] = cost[s.m.first][s.m.second][s.g.first][s.g.second][(turn+gp.size()-1)%gp.size()]+1;
						if(mn == gn){
							g = mn;
							gt =  turn;
						}
						q.push(S(mn,gn,gp[turn]));
					}
				}
				if(g.first != -1)
					break;
			}
			if(g.first != -1)
				break;
			++turn;
			turn%=gp.size();
		}
		if(g.first != -1)
			cout << cost[g.first][g.second][g.first][g.second][gt] << ' ' << g.first-1  << ' '<< g.second-1 << endl;
		else
			cout << "impossible" << endl;
	}
}

C++: #include<iostream>
#include<queue>
#include<string>
using namespace std;
int dist[21][21], x[21][21], sx, sy, gx, gy, H, W; string S;
int main() {
	while (true) {
		cin >> H >> W; if (H == 0 && W == 0)break;
		for (int i = 0; i < 441; i++)dist[i / 21][i % 21] = 99999;
		for (int i = 0; i < H; i++) {
			for (int j = 0; j < W; j++) {
				char c; cin >> c; dist[i][j] = 99999;
				if (c == 'A') { sx = i; sy = j; x[i][j] = 0; }
				if (c == 'B') { gx = i; gy = j; x[i][j] = 0; }
				if (c == '#') { x[i][j] = 1; }
				if (c == '.') { x[i][j] = 0; }
			}
		}
		queue<pair<int, int>>Q; Q.push(make_pair(sx, sy)); dist[sx][sy] = 0;
		int dx[4] = { 1,0,0,-1 }, dy[4] = { 0,-1,1,0 };
		while (!Q.empty()) {
			int a1 = Q.front().first, a2 = Q.front().second; Q.pop();
			for (int i = 0; i < 4; i++) {
				int cx = a1 + dx[i], cy = a2 + dy[i];
				if (cx < 0 || cy < 0 || cx >= H || cy >= W)continue;
				if (dist[cx][cy] > dist[a1][a2] + 1 && x[cx][cy] == 0) {
					dist[cx][cy] = dist[a1][a2] + 1;
					Q.push(make_pair(cx, cy));
				}
			}
		}
		cin >> S; for (int i = 0; i < 10; i++)S += S; bool OK = false;
		for (int i = 0; i < 1000; i++) {
			if (gx >= 0 && gx < H && gy >= 0 && gy < W) {
				if (dist[gx][gy] <= i) { cout << i << ' ' << gx << ' ' << gy << endl; OK = true; break; }
			}
			if (S[i] != '5') {
				gx += dx[(S[i] - '2') / 2]; gy += dy[(S[i] - '2') / 2];
				if (gx == -1)gx = 0; if (gx == H)gx = H - 1;
				if (gy == -1)gy = 0; if (gy == W)gy = W - 1;
			}
		}
		if (OK == false)cout << "impossible" << endl;
	}
	return 0;
}