hdu 1180 诡异的楼梯 BFS + 优先队列-白红宇

hdu 1180 诡异的楼梯 BFS + 优先队列

阅读量：5898 次

发布时间：2019-06-19

本文共 2150 字，大约阅读时间需要 7 分钟。

//#pragma comment(linker, "/STACK:1024000000,1024000000")#include
      
       #include
       
        #include
        
         #include
         
          #include
          
           #include
           
            #include
            
             #include
             
              #include
              
               #include
               #include
                
                 #include
                 
                  #include
                  
                   #include
                   
                    using namespace std;typedef long long ll;typedef unsigned long long ull;typedef pair
                    
                      pii;#define pb(a) push(a)#define INF 0x1f1f1f1f#define lson idx<<1,l,mid#define rson idx<<2|1,mid+1,r#define PI 3.1415926535898template
                     
                       T min(const T& a,const T& b,const T& c) { return min(min(a,b),min(a,c));}template
                      
                        T max(const T& a,const T& b,const T& c) { return max(max(a,b),max(a,c));}void debug() {#ifdef ONLINE_JUDGE#else freopen("d:\\in1.txt","r",stdin); freopen("d:\\out1.txt","w",stdout);#endif}int getch() { int ch; while((ch=getchar())!=EOF) { if(ch!=' '&&ch!='\n')return ch; } return EOF;}const int maxn=1000100;char grid[22][22];int vis[22][22];int dx[]={-1,0,1,0};int dy[]={ 0,1,0,-1};int n,m;struct point{ int x,y,t; bool operator < (const point &pt) const { return t>pt.t; }};int bfs(){ priority_queue
                       
                         q; memset(vis,0,sizeof(vis)); for(int i=1;i<=n;i++) for(int j=1;j<=m;j++) if(grid[i][j]=='S') { q.push((point){i,j,0}); vis[i][j]=1; break; } while(!q.empty()) { point pt=q.top();q.pop(); if(grid[pt.x][pt.y]=='T')return pt.t; for(int d=0;d<4;d++) { int nx=pt.x+dx[d]; int ny=pt.y+dy[d]; int nt=pt.t+1; if(nx>=1&&nx<=n&&ny>=1&&ny<=m) { if((grid[nx][ny]=='.'||grid[nx][ny]=='T')&&vis[nx][ny]!=1) { q.push( (point) {nx,ny,nt} ); vis[nx][ny]=1; } else if(grid[nx][ny]=='|') { if(nt%2==d%2)nt++; int nnx=nx+dx[d],nny=ny+dy[d]; if(nnx>=1&&nnx<=n&&nny>=1&&nny<=m&&!vis[nnx][nny]) { q.push( (point) {nnx,nny,nt} ); vis[nnx][nny]=1; } } else if(grid[nx][ny]=='-') { if(nt%2!=d%2)nt++; int nnx=nx+dx[d],nny=ny+dy[d]; if(nnx>=1&&nnx<=n&&nny>=1&&nny<=m&&!vis[nnx][nny]) { q.push( (point) {nnx,nny,nt} ); vis[nnx][nny]=1; } } } } } return -1;}int main(){ while(scanf("%d%d",&n,&m)!=EOF) { for(int i=1;i<=n;i++) scanf("%s",grid[i]+1); int num=bfs(); printf("%d\n",num); } return 0;}