Ultraviolet a 1600 patrol Robot

BFS with status

A number (KS) is used to indicate the State-the number of obstacles for the current continuous traversal;

Step indicates the number of current steps;

The visit array also adds a State;

 

 

 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 }