UVA 1600 Patrol Robot

带状态的bfs

用一个数（ks）来表示状态-当前连续穿越的障碍数；

step表示当前走过的步数；

visit数组也加一个状态；

 1 #include <iostream>
 2 #include <cstring>
 3 #include <cstdio>
 4 #include <queue>
 5 using namespace std;
 6
 7 const int maxn = 30 ;
 8
 9 struct node {
10     int x,y;
11     int step;
12     int ks;
13     void init (int nx,int ny,int nstep,int nks){
14         x=nx;y=ny;step=nstep;ks=nks;
15     }
16 };
17
18 int n,m,k;
19 int map[maxn][maxn],visit[maxn][maxn][maxn];
20 int dir[4][2]={1,0,-1,0,0,1,0,-1};
21
22 int bfs (){
23     queue<node> q;
24     while (!q.empty ())
25         q.pop ();
26     node a,b;
27     a.init (1,1,0,0);
28     q.push (a);
29     while (!q.empty ()){
30         a=q.front ();
31         q.pop ();
32
33         int xx,yy,sstep,kss;
34         for (int i=0;i<4;i++){
35             xx=a.x;yy=a.y;sstep=a.step;kss=a.ks;
36             xx+=dir[i][0];
37             yy+=dir[i][1];
38             sstep+=1;
39             if (xx<1||xx>n||yy<1||yy>m)
40                 continue ;
41             if (map[xx][yy])
42                 kss++;
43             else kss=0;
44             if (kss>k)
45                 continue ;
46             if (visit[kss][xx][yy])
47                 continue ;
48             if (xx==n&&yy==m)
49                 return sstep ;
50             b.init (xx,yy,sstep,kss);
51             q.push (b);
52             visit[kss][xx][yy]=1;
53         }
54     }
55     return -1;
56 }
57
58 int main (){
59     int t;
60     cin>>t;
61     while (t--){
62         cin>>n>>m>>k;
63         if (n==m&&n==1){
64             cout<<0<<"error"<<endl;
65             continue ;
66         }
67         memset (visit,0,sizeof visit);
68         for (int i=1;i<=n;i++)
69             for (int j=1;j<=m;j++)
70                 cin>>map[i][j];
71         int ans=bfs ();
72         cout<<ans<<endl;
73     }
74     return 0;
75 }

UVA 1600 Patrol Robot