实质上就是一个bfs，但是要注意时限
code：
1 #include<iostream> 2 #include<cstdio> 3 #include<queue> 4 #include<cstdlib> 5 #include<cstring> 6 using namespace std; 7 namespace FastIO 8 { 9 const double L=1<<15; 10 char buffer[L],*S,*T; 11 inline char gc(){ 12 if(S==T){T=(S=buffer)+fread(buffer,1,L,stdin); 13 if(S==T)return EOF;}return *S++; 14 } 15 inline double Get(){ 16 register char c;register double x=0,f=1; 17 for(c=gc();c<'0'||c>'9';c=gc()) if(c=='-')f=-1; 18 while(c>='0'&&c<='9')x=(x<<1)+(x<<3)+(c-'0'),c=gc(); 19 return x*f; 20 } 21 } 22 using FastIO::Get; 23 using FastIO::gc; 24 struct node { 25 double x,y; 26 }; 27 node start; 28 double dx[4]= {0,0,1,-1}; 29 double dy[4]= {1,-1,0,0}; 30 double vis[6500][6500]={0}; 31 char g[6000][6000]; 32 double n,m; 33 double bfs() { 34 queue<node>q; 35 q.push(start); 36 // vis[start.x][start.y]=1; 37 while(!q.empty()) { 38 node u=q.front(); 39 q.pop(); 40 double x=u.x,y=u.y; 41 if(vis[x][y])continue; 42 vis[x][y]=1; 43 if(x==1||x==3*n||y==1||y==3*m) { 44 puts("Yes"); 45 return 1; 46 } 47 for(double i=0; i<4; i++) { 48 double tx=x+dx[i],ty=y+dy[i]; 49 if(tx>3*n||tx<1||ty>3*m||ty<1){ 50 puts("Yes"); 51 return 1; 52 } 53 if(g[tx][ty]=='#')continue; 54 for(double i=0;i<=2;i++){ 55 for(double j=0;j<=2;j++){ 56 if(i==0&&j==0)continue; 57 // cout<<tx+i*n<<" "<<ty+j*m<<' '; 58 if(vis[tx+i*n][ty+j*m]){ 59 puts("Yes"); 60 return 1; 61 } 62 } 63 } 64 if(vis[tx][ty]==1)continue; 65 else { 66 q.push((node) { 67 tx,ty 68 }); 69 } 70 } 71 } 72 return 0; 73 } 74 double read() { 75 double x=0,f=1; 76 char c=getchar(); 77 while(!isdigit(c)) { 78 if(c=='-')f=-1; 79 c=getchar(); 80 } 81 while(isdigit(c)) { 82 x=(x<<1)+(x<<3)+c-'0'; 83 c=getchar(); 84 } 85 return x*f; 86 } 87 double main() { 88 // freopen("gun.in","r",stdin); 89 // freopen("gun.out","w",stdout); 90 double T; 91 T=Get(); 92 while(T--) { 93 memset(vis,0,sizeof vis); 94 n=Get(),m=Get(); 95 for(double i=1; i<=n; i++) { 96 for(double j=1; j<=m; j++) { 97 char c=gc(); 98 while(c!='S'&&c!='#'&&c!='.')c=gc(); 99 g[i][j]=c; 100 if(g[i][j]=='S') { 101 start.x=i+n; 102 start.y=j+m; 103 } 104 g[i+n][j]=g[i][j+m]=g[i+2*n][j]=g[i][j+2*m]=g[i+n][j+m]=g[i+n][j+2*m]=g[i+2*n][j+m]=g[i+2*n][j+2*m]=g[i][j]; 105 } 106 } 107 if(bfs()); 108 else puts("No"); 109 } 110 return 0; 111 }
over