HDU 1242 简单bfs

#include <iostream>
#include <queue>
using namespace std;
int n, m;
const int MAX = 205;
char a[MAX][MAX], map[MAX][MAX];
int dir[4][2] = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
struct node
{
	int x, y, step;
};
void bfs()
{
	int i, j;
	struct node cur, next, end;
	for(i = 0; i < n; i++)
		for(j = 0; j < m; j++)
		{
			if(a[i][j] == 'r')
			{
				cur.x = i;
				cur.y = j;
				cur.step = 0;
			}
			if(a[i][j] == 'a')
			{
				end.x = i;
				end.y = j;
			}
		}

	if(cur.x == end.x && cur.y == end.y)
	{
		cout << 0 << endl;
		return;
	}

	queue<node> q;
	q.push(cur);
	while(!q.empty())
	{
		cur = q.front();
		q.pop();
		for(i = 0; i < 4; i++)
		{
			next.x = cur.x + dir[i][0];
			next.y = cur.y + dir[i][1];
			next.step = cur.step + 1;
			if(next.x == end.x && next.y == end.y)
			{
				cout << next.step << endl;
				return;
			}
			if(next.x >= 0 && next.x < n && next.y >= 0 && next.y < m && map[next.x][next.y] == 0)
			{
				map[next.x][next.y] = 1;
				if(a[next.x][next.y] == 'x')
					next.step += 1;
				if(a[next.x][next.y] == '#')
					continue;
				q.push(next);				
			}
		}
	}
	cout << "Poor ANGEL has to stay in the prison all his life." << endl;
}
int main()
{
	int i, j;
	while(scanf("%d%d", &n, &m) != EOF)
	{
		memset(map, 0, sizeof(map));
		for(i = 0; i < n; i++)
			scanf("%s", a+i);
		bfs();
	}
	return 0;
}