HDU 1242(bfs)

#include <iostream>
#include <queue>
#include <string>
#include <sstream>
using namespace std;

struct Point
{
int x, y, time;
bool operator <(const Point& rhs) const
{
return time > rhs.time;
}
} a;

int direction[4][2] = { {1, 0}, {-1, 0}, {0, -1}, {0, 1} };

void getXY(string* matrix, int n, int m)
{
for (int i = 1; i <= n; ++i)
for (int j = 1; j <= m; ++j)
if (matrix[i][j] == 'a')
{
a.x = i;
a.y = j;
a.time = 0;
return;
}
}

int result(string* matrix)
{
Point t;
priority_queue<Point> q;
Point p;
q.push(a);
while (!q.empty())
{
p = q.top();
q.pop();
for (int i = 0; i < 4; ++i)
{
t.x = p.x + direction[i][0];
t.y = p.y + direction[i][1];
if (matrix[t.x][t.y] == '#')
continue;
t.time = p.time + 1;
if (matrix[t.x][t.y] == 'r')
return t.time;
if (matrix[t.x][t.y] == 'x')
t.time += 1;
matrix[t.x][t.y] = '#';
q.push(t);
}
}
return -1;
}

int main()
{
int n, m, i;
string line;
string matrix[202];
while (cin >> n >> m)
{
getchar();
for (i = 1; i <= n; ++i)
{
getline(cin, matrix[i]);
matrix[i] = '#' + matrix[i] + '#';
}
matrix[n+1] = matrix[0] = string(m+2, '#');
getXY(matrix, n, m);
i = result(matrix);
if (i == -1)
cout << "Poor ANGEL has to stay in the prison all his life.\n";
else cout << i << endl;
}
}