BZOJ2424: [HAOI2010]订货

  1 const inf=maxlongint;
  2 type node=record
  3      from,go,next,v,c:longint;
  4      end;
  5 var e:array[0..2000000] of node;
  6     pre,head,q,d:array[0..1000000] of longint;
  7     v:array[0..1000000] of boolean;
  8     i,j,n,m,maxf,s,t,l,r,mincost,tot,x:longint;
  9 function min(x,y:longint):longint;
 10  begin
 11  if x<y then exit(x) else exit(y);
 12  end;
 13 procedure ins(x,y,z,w:longint);
 14  begin
 15  inc(tot);
 16  with e[tot] do
 17   begin
 18   from:=x;go:=y;v:=z;c:=w;next:=head[x];head[x]:=tot;
 19   end;
 20  end;
 21 procedure insert(x,y,z,w:longint);
 22  begin
 23  ins(x,y,z,w);ins(y,x,0,-w);
 24  end;
 25 function spfa:boolean;
 26  var i,x,y:longint;
 27  begin
 28  fillchar(v,sizeof(v),false);
 29  for i:=s to t do d[i]:=inf;
 30  l:=0;r:=1;q[1]:=s;d[s]:=0;v[s]:=true;
 31  while l<r do
 32   begin
 33   inc(l);
 34   x:=q[l];v[x]:=false;
 35   i:=head[x];
 36   while i<>0 do
 37    begin
 38    y:=e[i].go;
 39    if (e[i].v<>0) and (d[x]+e[i].c<d[y]) then
 40     begin
 41     d[y]:=d[x]+e[i].c;
 42     pre[y]:=i;
 43     if not(v[y]) then
 44      begin
 45      v[y]:=true;
 46      inc(r);
 47      q[r]:=y;
 48      end;
 49     end;
 50    i:=e[i].next;
 51   end;
 52  end;
 53  exit(d[t]<>inf);
 54  end;
 55 procedure mcf;
 56  var i,tmp:longint;
 57  begin
 58  mincost:=0;
 59  while spfa do
 60   begin
 61   tmp:=inf;
 62   i:=pre[t];
 63   while i<>0 do
 64    begin
 65    tmp:=min(tmp,e[i].v);
 66    i:=pre[e[i].from];
 67    end;
 68   inc(mincost,tmp*d[t]);
 69   i:=pre[t];
 70   while i<>0 do
 71    begin
 72    dec(e[i].v,tmp);
 73    inc(e[i xor 1].v,tmp);
 74    i:=pre[e[i].from];
 75    end;
 76   end;
 77  end;
 78 procedure init;
 79  begin
 80  tot:=1;
 81  readln(n,m,maxf);
 82  s:=0;t:=2*n+1;
 83  for i:=1 to n do
 84   begin
 85   read(x);
 86   insert(i+n,t,x,0);
 87   insert(i,i+n,maxf+x,0);
 88   end;
 89  for i:=1 to n do
 90   begin
 91   read(x);
 92   insert(s,i,inf,x);
 93   end;
 94  for i:=1 to n-1 do insert(i+n,i+1,inf,m);
 95  end;
 96 procedure main;
 97  begin
 98  mincost:=0;
 99  mcf;
100  writeln(mincost);
101  end;
102 begin
103  assign(input,‘input.txt‘);assign(output,‘output.txt‘);
104  reset(input);rewrite(output);
105  init;
106  main;
107  close(input);close(output);
108 end.