bzoj 1066: [SCOI2007]蜥蜴

拆点构图最大流

代码:

var  u,l,n,m,i,j,ans,tot,s,t,x,e,d1,num:longint;  c:array[1..1000,1..1000] of longint;  fa:array[0..1000] of longint;  a:array[1..20,1..20] of char;  s1:string;  w:char; procedure work(x,y:longint);var  i,j,p1,q1,p2,q2:longint;begin  for i:=1 to n do    for j:=1 to m do      if (sqrt(sqr(i-x)+sqr(j-y))<=d1)and(a[i,j]<>'0')and((i<>x)or(j<>y)) then      begin        p1:=((i-1)*m+j)*2-1;        q1:=((i-1)*m+j)*2;        p2:=((x-1)*m+y)*2-1;        q2:=((x-1)*m+y)*2;        c[q2,p1]:=maxlongint;        c[q1,p2]:=maxlongint;      end;end; function find(x:longint):boolean;var  i:longint;begin  if x=t then exit(true);  find:=false;  for i:=1 to n*2*m+2 do    if (fa[i]=-1)and(c[x,i]>0) then    begin      fa[i]:=x;      if find(i) then exit(true);    end;end; procedure change;var  min,i:longint;begin  min:=maxlongint;  i:=t;  while i<>s do  begin    if c[fa[i],i]<min then min:=c[fa[i],i];    i:=fa[i];  end;  ans:=ans+min;  i:=t;  while i<>s do  begin    dec(c[fa[i],i]);    inc(c[i,fa[i]]);    i:=fa[i];  end;end; procedure main;var  i:longint;begin  for i:=1 to n*m*2+2 do    fa[i]:=-1;  fa[s]:=0;  while find(s) do  begin    change;    for i:=1 to n*m*2+2 do      fa[i]:=-1;    fa[s]:=0;  end;end; begin    readln(n,m,d1);    for i:=1 to n do      for j:=1 to m do        if j<m          then read(a[i,j])          else readln(a[i,j]);    for i:=1 to n do      for j:=1 to m do        if a[i,j]<>'0' then        begin          val(a[i,j],x);          c[((i-1)*m+j)*2-1,((i-1)*m+j)*2]:=x;;        end;    for i:=1 to n do      for j:=1 to m do        if a[i,j]<>'0' then work(i,j);    s:=n*m*2+1;    t:=n*m*2+2;    tot:=0;    for i:=1 to n do      for j:=1 to m do      begin        if j<m          then read(w)          else readln(w);        if w='L' then        begin          inc(tot);          c[s,((i-1)*m+j)*2-1]:=1;        end;      end;    for i:=1 to n do      for j:=1 to m do        if (a[i,j]<>'0')and((i<=d1)or(j<=d1)or(n-i+1<=d1)or(m-j+1<=d1)) then          c[((i-1)*m+j)*2,t]:=maxlongint;    ans:=0;    main;    write(tot-ans);end.