洛谷1126-BFS
题目链接 https://www.luogu.org/problemnew/show/P1126
1 #include<iostream> 2 #include<cstring> 3 #include<queue> 4 using namespace std; 5 bool map[51][51]; 6 int vis[51][51][5]; 7 struct node{ 8 int x,y,dir,step; 9 }; 10 queue<node> q; 11 node aaa; 12 int tx,ty,f,st,x1,x2,y1,y2,n,m; 13 int fx[4]={0,1,0,-1},fy[4]={1,0,-1,0}; 14 void bfs() 15 { 16 while(!q.empty()){ 17 aaa=q.front(); 18 q.pop(); 19 tx=aaa.x; 20 ty=aaa.y; 21 if(tx==x2&&ty==y2){ 22 cout<<aaa.step; 23 return; 24 } 25 for(int j=1;j<=3;j++){ 26 tx+=fx[aaa.dir]; 27 ty+=fy[aaa.dir]; 28 if(tx<=0||ty<=0||tx>=n||ty>=m||map[tx][ty]==1) 29 break; 30 else if(!vis[tx][ty][aaa.dir]){ 31 vis[tx][ty][aaa.dir]=true; 32 node cnew; 33 cnew.x=tx; 34 cnew.y=ty; 35 cnew.dir=aaa.dir; 36 cnew.step=aaa.step+1; 37 q.push(cnew); 38 } 39 } 40 node cnew; 41 cnew.x=aaa.x; 42 cnew.y=aaa.y; 43 cnew.step=aaa.step+1; 44 cnew.dir=aaa.dir-1; 45 if(cnew.dir==-1) cnew.dir=3;//如果dir=-1的话，就相当于由东向北 46 if(!vis[cnew.x][cnew.y][cnew.dir]){ 47 vis[cnew.x][cnew.y][cnew.dir]=true; 48 q.push(cnew); 49 } 50 cnew.dir=aaa.dir+1; 51 if(cnew.dir==4) cnew.dir=0; 52 if(!vis[cnew.x][cnew.y][cnew.dir]){ 53 vis[cnew.x][cnew.y][cnew.dir]=true; 54 q.push(cnew); 55 } 56 } 57 cout<<"-1"; 58 } 59 int main() 60 { 61 cin>>n>>m; 62 for(int i=1;i<=n;i++){ 63 for(int j=1;j<=m;j++){ 64 bool a; 65 cin>>a; 66 if(a){ 67 map[i][j]=1; 68 map[i-1][j]=1; 69 map[i-1][j-1]=1; 70 map[i][j-1]=1; 71 } 72 } 73 } 74 for(int i=1;i<=n;i++){ 75 map[n][i]=1; 76 map[i][m]=1; 77 } 78 char fang; 79 cin>>x1>>y1>>x2>>y2>>fang; 80 if(fang=='E') aaa.dir=0; 81 else if(fang=='S') aaa.dir=1; 82 else if(fang=='W') aaa.dir=2; 83 else aaa.dir=3; 84 aaa.x=x1; 85 aaa.y=y1; 86 q.push(aaa); 87 bfs(); 88 return 0; 89 }
