Language: C++

#include <stdio.h>
#include <list>

using namespace std;

//#define DEBUG

typedef struct {
	int px, py;
	int gx, gy;
	int move_index;
	int depth;
} DATA;


char map[20 + 2][20 + 2];
char move_inst[11];
list<unsigned> lstHash;
list<DATA> lstSarch;

unsigned calc_hash(const DATA& data)
{
	unsigned hash;
	
	hash = data.px | (data.py << 5) | (data.gx << 10) | (data.gy << 15) | (data.move_index << 20);
	
	return (hash);
}

bool is_add(const DATA& data)
{
	unsigned hash;
	
	hash = calc_hash(data);
	if (map[data.px][data.py] == -1 || map[data.px][data.py] == '#' || find(lstHash.begin(), lstHash.end(), hash) != lstHash.end()){
		return (false);
	}
	
	return (true);
}

int width_priority_sarch(const DATA& data)
{
	DATA add;
	
	add.depth = data.depth + 1;
	add.move_index = (data.move_index + 1) % strlen(move_inst);
	
	add.gx = data.gx;
	add.gy = data.gy;
	switch (move_inst[data.move_index]){
	  case '8': add.gy--; break;
	  case '4': add.gx--; break;
	  case '6': add.gx++; break;
	  case '2': add.gy++; break;
	  default :           break;
	}
	
	if (map[add.gx][add.gy] == -1){
		add.gx = data.gx;
		add.gy = data.gy;
	}
	
	add.px = data.px;
	add.py = data.py;
	if (is_add(add) == true){
		lstSarch.push_back(add);
		lstHash.push_back(calc_hash(add));
	}
#ifdef DEBUG
	printf("%d %d\n", add.move_index, data.move_index);
	printf("%u %u\n", calc_hash(add), calc_hash(data));
#endif
	
	add.px++;
	if (is_add(add) == true){
		lstSarch.push_back(add);
		lstHash.push_back(calc_hash(add));
	}
	add.px = data.px;
	add.px--;
	if (is_add(add) == true){
		lstSarch.push_back(add);
		lstHash.push_back(calc_hash(add));
	}
	add.px = data.px;
	add.py++;
	if (is_add(add) == true){
		lstSarch.push_back(add);
		lstHash.push_back(calc_hash(add));
	}
	add.py = data.py;
	add.py--;
	if (is_add(add) == true){
		lstSarch.push_back(add);
		lstHash.push_back(calc_hash(add));
	}
	
	return (0);
}

bool is_end(DATA& data)
{
	if (data.px == data.gx && data.py == data.gy){
		return (true);
	}
	return (false);
}

int main(void)
{
	DATA start;
	int hight, with;
	
	while (1){
		lstHash.clear();
		lstSarch.clear();
		
		scanf("%d%d", &hight, &with);
		
		if (hight == 0 || with == 0){
			break;
		}
		
		for (int i = 0; i < 22; i++){
			for (int j = 0; j < 22; j++){
				map[i][j] = -1;
			}
		}
		for (int y = 0; y < hight; y++){
			char str[21];
			scanf("%s", str);
			for (int x = 0; x < with; x++){
				map[x + 1][y + 1] = str[x];
				if (map[x + 1][y + 1] == 'A'){
					start.px = x + 1;
					start.py = y + 1;
					map[x + 1][y + 1] = '.';
				}
				if (map[x + 1][y + 1] == 'B'){
					start.gx = x + 1;
					start.gy = y + 1;
					map[x + 1][y + 1] = '.';
				}
			}
		}
		scanf("%s", move_inst);
		start.move_index = 0;
		start.depth = 0;
		
		lstHash.push_back(calc_hash(start));
		lstSarch.push_back(start);
		
		while (lstSarch.empty() == false && is_end(lstSarch.front()) == false){
#ifdef DEBUG
			printf("%d %d %d %d %d %d\n", lstSarch.front().px, lstSarch.front().py, lstSarch.front().gx, lstSarch.front().gy, lstSarch.front().depth, lstSarch.front().move_index);
#endif
			width_priority_sarch(lstSarch.front());
			lstSarch.pop_front();
		}
		
		if (lstSarch.empty() == true){
			puts("impossible");
		}
		else {
			printf("%d %d %d\n", lstSarch.front().depth, lstSarch.front().py - 1, lstSarch.front().px - 1);
		}
	}
	
	return (0);
}

Compiler output:
a.cc: In function 'bool is_add(const DATA&)':
a.cc:35:76: error: 'find' was not declared in this scope
   35 |         if (map[data.px][data.py] == -1 || map[data.px][data.py] == '#' || find(lstHash.begin(), lstHash.end(), hash) != lstHash.end()){
      |                                                                            ^~~~
a.cc: In function 'int width_priority_sarch(const DATA&)':
a.cc:47:50: error: 'strlen' was not declared in this scope
   47 |         add.move_index = (data.move_index + 1) % strlen(move_inst);
      |                                                  ^~~~~~
a.cc:3:1: note: 'strlen' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
    2 | #include <list>
  +++ |+#include <cstring>
    3 |