hdu 1242 Rescue（广搜+优先队列）

#include<iostream>
#include<string>
#include<cstring>
#include<queue>
#define N 210
using namespace std;
int n, m, mark

, dir[4][2] = {{1,0}, {-1,0}, {0,1}, {0,-1}};
int s_x, s_y, e_x, e_y;
char str

;

struct node
{
int x, y, step;
friend bool operator < (node n1, node n2)
{
return n2.step < n1.step;
}
};

int judge(int x, int y)
{
if(x>=0 && x<n && y>=0 && y<m && mark[x][y]!=1 && str[x][y] != '#')
return 1;
else
return 0;
}

int bfs()
{
int x, y, i;
node cur, next;
priority_queue<node>q;
cur.x=s_x; cur.y=s_y; cur.step=0;
q.push(cur);
while(!q.empty())
{
cur = q.top();
q.pop();
if(cur.x==e_x && cur.y==e_y) return cur.step;
for(i=0; i < 4; i++ )
{
next.x = x = cur.x + dir[i][0];
next.y = y = cur.y + dir[i][1];
next.step = cur.step + 1;

if(judge(x, y))
{
mark[x][y] = 1;
if(str[x][y] == 'x')
next.step++;
q.push(next);
}
}
}
return -1;
}

int main()
{
int i, j;
while(scanf("%d%d", &n, &m) != -1)
{
for( i=0; i < n; i++ )
scanf("%s", str[i]);

for( i=0; i < n; i++ )
{
for( j=0; j < m; j++ )
{
if(str[i][j] == 'a')
e_x=i, e_y=j;
if(str[i][j] == 'r')
s_x=i, s_y=j;
}
}
memset(mark, 0, sizeof(mark));
int ans = bfs();
if(ans == -1)
printf("Poor ANGEL has to stay in the prison all his life.\n");
else
printf("%d\n", ans);
}
return 0;
}