Bzoj 2007 Altitude

http://www.lydsy.com/JudgeOnline/problem.php?id=2007

Ideas:

Obviously the elevation is a 0, another 1, the answer is 01 of the dividing line of traffic.

The figure in the subject is a plan, so the minimum cut can be converted to the shortest path of the dual graph, according to Gword said: There is a unified to the edge of the 90 ° clockwise, and also, to the first S and T edge, to "split" the outermost space, and then the S and t separate.

1#include <algorithm>2#include <cstdio>3#include <cmath>4#include <cstring>5#include <iostream>6#include <queue>7 using namespacestd;8 intfirst[250005],next[2000005],go[2000005],tot,val[2000005];9 intdis[250005],vis[250005],s,t,n;Ten intRead () { One     CharCh=getchar ();intt=0, f=1; A      while(ch<'0'|| Ch>'9'){if(ch=='-') f=-1; ch=GetChar ();} -      while('0'<=ch&&ch<='9') {t=t*Ten+ch-'0'; ch=GetChar ();} -     returnt*F; the } - voidInsertintXintYintz) { -tot++; -go[tot]=y; +next[tot]=First[x]; -first[x]=tot; +val[tot]=Z; A } at voidAddintXintYintz) { - Insert (x, y, z); - } - intIdintXinty) { -     if(x==0|| y==n+1)returnT; -     if(x==n+1|| y==0)returnS; in     return(X-1) *n+y; - } to voidDijkstra () { +memset (DIS,127/3,sizeofdis); -priority_queue< pair<int,int>,vector< pair<int,int> >,greater<pair<int,int> > >Q; thedis[s]=0; *Q.push (Make_pair (0, S)); $      while(!Q.empty ()) {Panax Notoginseng         intnow=Q.top (). Second; Q.pop (); -         if(Vis[now])Continue; thevis[now]=1; +          for(intI=first[now];i;i=Next[i]) { A             intPur=Go[i]; the             if(dis[pur]>dis[now]+Val[i]) { +dis[pur]=dis[now]+Val[i]; - Q.push (Make_pair (Dis[pur],pur)); $             } $         } -     } - } the intMain () { -n=read ();Wuyis=0, t=n*n+1; the      for(intI=1; i<=n+1; i++) -       for(intj=1; j<=n;j++) WuAdd (ID (I,J), id (i-1, J), read ()); -      for(intI=1; i<=n;i++) About       for(intj=1; j<=n+1; j + +) $Add (ID (i,j-1), ID (i,j), read ());  -      for(intI=1; i<=n+1; i++) -       for(intj=1; j<=n;j++) -Add (ID (i-1, J), ID (i,j), read ());  A      for(intI=1; i<=n;i++) +       for(intj=1; j<=n+1; j + +) theAdd (ID (I,J), ID (i,j-1), read ()); - Dijkstra ();  $printf"%d\n", Dis[t]); the}

Bzoj 2007 Altitude