(BFS) Hdoj1242-rescue

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Beginner BFS, the first time to use BFS to do the problem. The problem is a basic BFS model, which requires a little attention to +1 of the guard time, and the shortest time rather than the number of steps.

1#include <cstdio>2#include <cstring>3#include <queue>4 #defineS 2055 #defineINF 1000006 using namespacestd;7 structLo//build a structure, store point coordinates, and some way to get here. Number of steps and time8 {9     intX,y,step,time;Ten }; OneQueue<lo> Q;//set up a queue and store nodes. A intmintime[s][s],dir[4][2]={{0,1},{0,-1},{-1,0},{1,0}},m,n,si,sj,ei,ej;//Si, SJ storage starting point, mintime storage to a certain point in the shortest time, initialized to INF - CharTem[s][s];//Store Map - intBFS (lo x) the { -     inti; - Q.push (x); - Lo hd; +      while(!q.empty ())//To find the optimal solution, you need to wait until the queue is empty to stop -     { +Hd=q.front ();//take out the queue header and proceed from the node of the queue header.  A Q.pop (); at          for(i=0;i<4; i++) -         { -             intx=hd.x+dir[i][0],y=hd.y+dir[i][1]; -             if(x>=0&&x<m&&y>=0&&y<n&&tem[x][y]!='#')//If one step in one direction is feasible, then it is possible to determine whether this is the shortest. If yes, then press in -             { - Lo t; int.x=x;t.y=y;t.time=hd.time+1; t.step=hd.step+1; -                 if(tem[x][y]=='x') t.time++;//if it's a guard, it's +1 hours. to                 if(T.time<mintime[x][y])//there may be a shorter way to get here, but since each is put in a queue, it will continue from here . +{mintime[x][y]=T.time; - Q.push (t); the                 } *             } $         }Panax Notoginseng     } -     returnMintime[ei][ej];//Back to answers the } + intMain () A { the      while(~SCANF ("%d%d",&m,&N)) +     { -memset (TEM,0,sizeof(TEM)); $         intI,j,an; $          for(i=0; i<m;i++) -         { -scanf"%s", Tem[i]); the         } -          for(i=0; i<m;i++)Wuyi         { the              for(j=0; j<n;j++) -             { WuMintime[i][j]=inf;//initialization time is INF -                 if(tem[i][j]=='a') About                 { $ei=i;ej=J; -                 } -                 Else if(tem[i][j]=='R') -                 { Asi=i;sj=J; +                 } the             } -         } $ Lo t; thet.x=si;t.y=sj;t.step=0; t.time=0; mintime[si][sj]=0; thean=BFS (t); the         if(an<INF) theprintf"%d\n", an); -         Else inprintf"Poor ANGEL have to stay in the prison all his life.\n"); the     } the     return 0; About}

(BFS) Hdoj1242-rescue