Problem solving: Usaco13jan Island Travels

Surface

As if there is nothing to say, just practice the code force ...

First run out of the island with BFs, and then run the shortest way to find the distance between the islands, the final pressure DP to come to the answer

Attention to detail, code code 2333

1#include <Set>2#include <queue>3#include <cstdio>4#include <cstring>5#include <algorithm>6 using namespacestd;7 Const intn= -, m= the, l= -;8 Const intmov[4][2]={{0,1},{0,-1},{1,0},{-1,0}};9 structaTen { One     intXx,yy; A}que[l*L]; - CharMapp[l][l]; - intval[n][n],dp[1<<N] [N]; the intMapp[l][l],vis[l][l],dis[l][l]; - intn,m,f,b,nx,ny,land,shal,nde,all,ans=2e9; -Deque<a>Qs; - BOOLOk1 (intXinty) + { -     returnmapp[x][y]=='X'&&! mapp[x][y]&&x>=1&&x<=n&&y>=1&&y<=m; + } A voidBFS1 (intXinty) at { -que[f=b=0]= (a) {x,y},mapp[x][y]=++Land ; -      while(f<=b) -     { -A tn=que[f++]; -         inttx=tn.xx,ty=tn.yy; in          for(intI=0;i<4; i++) -              if(Ok1 (nx=tx+mov[i][0],ny=ty+mov[i][1])) tomapp[nx][ny]=land,que[++b]=(a) {nx,ny}; +     } - } the BOOLOK2 (intXinty) * { $     returnmapp[x][y]=='S'&&! mapp[x][y]&&x>=1&&x<=n&&y>=1&&y<=m;Panax Notoginseng } - voidBFS2 (intXinty) the { +que[f=b=0]= (a) {x,y},mapp[x][y]=--Shal; A      while(f<=b) the     { +A tn=que[f++]; -         inttx=tn.xx,ty=tn.yy; $          for(intI=0;i<4; i++) $              if(Ok2 (nx=tx+mov[i][0],ny=ty+mov[i][1])) -mapp[nx][ny]=shal,que[++b]=(a) {nx,ny}; -     } the } - BOOLOkintXinty)Wuyi { the     returnmapp[x][y]&&!vis[x][y]&&x>=1&&x<=n&&y>=1&&y<=m; - } Wu voidBFS (intXinty) - { About Qs.push_back ((a) {x, y}); $memset (Vis,0,sizeofvis); -memset (DIS,0,sizeofdis); -nde=mapp[x][y],val[nde][nde]=0, vis[x][y]=true; -      while(!qs.empty ()) A     { +a Tt=qs.front (); Qs.pop_front ();inttx=tt.xx,ty=tt.yy; the          for(intI=0;i<4; i++) -             if(OK (nx=tx+mov[i][0],ny=ty+mov[i][1])) $             { thevis[nx][ny]=true; the                 if(mapp[tx][ty]<0) dis[nx][ny]=dis[tx][ty]+1, Qs.push_back ((a) {nx,ny}); the                 Else if(mapp[tx][ty]>0) dis[nx][ny]=Dis[tx][ty],qs.push_front ((a) {nx,ny}); the             } -     } in      for(intI=1; i<=n;i++) the          for(intj=1; j<=m;j++) the             if(mapp[i][j]>0)  Aboutval[nde][mapp[i][j]]=min (val[nde][mapp[i][j]],dis[i][j]); the } the intInsintNDE) the { +     return 1<< (nde-1); - } the intMain ()Bayi { thescanf"%d%d",&n,&m); the      for(intI=1; i<=n;i++) -scanf"%s", mapp[i]+1); -      for(intI=1; i<=n;i++) the          for(intj=1; j<=m;j++)     the             if(Ok1 (i,j)) BFS1 (i,j); the             Else if(Ok2 (i,j)) BFS2 (i,j); theMemset (Val,0x3f,sizeofval); -      for(intI=1; i<=n;i++) the          for(intj=1; j<=m;j++) the             if(mapp[i][j]>0) BFS (i,j); theAll= (1<<land)-1; 94Memset (DP,0x3f,sizeofDP); the      for(intI=1; i<=land;i++) Dp[ins (i)][i]=0; the      for(intI=0; i<=all;i++) the          for(intj=1; j<=land;j++)    98             if(i&ins (j)) About                  for(intk=1; k<=land;k++) -                     if(! (I&ins (k)) &&j!=k)101Dp[i|ins (k)][k]=min (Dp[i|ins (k)][k],dp[i][j]+val[j][k]);102      for(intI=1; i<=land;i++) ans=min (ans,dp[all][i]);103printf"%d", ans);104     return 0; the}

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Problem solving: Usaco13jan Island Travels