hdu 1242 Rescue(bfs+优先队列)

  1 /*************************************************************************
  2     > File Name: code/hdu/1242.cpp
  3     > Author: 111qqz
  4     > Email: rkz2013@126.com 
  5     > Created Time: 2015年10月02日 星期五 14时38分17秒
  6  ************************************************************************/
  7 
  8 #include<iostream>
  9 #include<iomanip>
 10 #include<cstdio>
 11 #include<algorithm>
 12 #include<cmath>
 13 #include<cstring>
 14 #include<string>
 15 #include<map>
 16 #include<set>
 17 #include<queue>
 18 #include<vector>
 19 #include<stack>
 20 #include<cctype>
 21 using namespace std;
 22 #define yn hez111qqz
 23 #define j1 cute111qqz
 24 #define ms(a,x) memset(a,x,sizeof(a))
 25 #define lr dying111qqz
 26 const int dx4[4]={1,0,0,-1};
 27 const int dy4[4]={0,-1,1,0};
 28 typedef long long LL;
 29 typedef double DB;
 30 const int inf = 0x3f3f3f3f;
 31 const int N=2E2+5;
 32 char maze[N][N];
 33 int m,n;
 34 int ans;
 35 bool vis[N][N];
 36 struct node
 37 {
 38     int x,y;
 39     int d;
 40 
 41     bool ok ()
 42     {
 43     if (x>=0&&x<n&&y>=0&&y<m&&!vis[x][y]&&maze[x][y]!=‘#‘) return true;
 44     return false;
 45     }
 46     bool hasguard()
 47     {
 48     if (maze[x][y]==‘x‘) return true;
 49     return false;
 50     }
 51     bool goal()
 52     {
 53     if (maze[x][y]==‘r‘) return true;
 54     return false;
 55     }
 56 }s;
 57 
 58 bool operator<(const node &a,const node &b)    //重载优先级的<关系...返回true时优先级更小，在队列的更后面．
 59 {
 60     return a.d>b.d;
 61 }
 62 
 63 bool bfs()
 64 {
 65     priority_queue<node>q;
 66     q.push(s);
 67     
 68     while (!q.empty())
 69     {
 70     node pre = q.top();
 71     q.pop();
 72 //    cout<<pre.x<<" "<<pre.y<<" "<<pre.d<<endl;
 73     if (pre.goal())
 74     {
 75         ans = pre.d;
 76         return true;
 77     }
 78 
 79     for ( int i = 0 ; i < 4 ; i++)
 80     {
 81         node next;
 82         next.x = pre.x + dx4[i];
 83         next.y = pre.y + dy4[i];
 84         next.d = pre.d + 1;
 85         if (!next.ok()) continue;
 86         vis[next.x][next.y] = true;
 87         if (next.hasguard()) next.d++;
 88         q.push(next);
 89         
 90 
 91     }
 92     }
 93     return false;
 94 }
 95 int main()
 96 {
 97   #ifndef  ONLINE_JUDGE 
 98    freopen("in.txt","r",stdin);
 99   #endif
100     while(scanf("%d %d",&n,&m)!=EOF){
101     ms(vis,false);
102     for ( int i = 0 ; i < n ; i++) scanf("%s",maze[i]);
103     for ( int i = 0 ; i < n ; i++)
104     {
105     for ( int j = 0 ; j < m ; j++)
106     {
107         if (maze[i][j]==‘a‘)
108         {
109         s.x = i ;
110         s.y = j ;
111         s.d = 0 ;
112         vis[i][j] = true;
113         break;
114         }
115     }
116     }
117 
118     if (bfs())
119     {
120     printf("%d\n",ans);
121     }
122     else
123     {
124     puts("Poor ANGEL has to stay in the prison all his life.");
125     }
126 }
127  #ifndef ONLINE_JUDGE  
128   fclose(stdin);
129   #endif
130     return 0;
131 }