BZOJ1305: [CQOI2009]dance跳舞

  1 const inf=maxlongint;maxn=5000;maxm=500000;
  2 type node=record
  3      from,go,next,v:longint;
  4      end;
  5 var  tot,i,j,n,m,maxflow,l,r,s,t,x,y,cnt:longint;
  6      h,head,q,cur:array[0..2*maxn] of longint;
  7      e:array[0..2*maxm] of node;
  8      num:array[0..2*maxn,1..3] of longint;
  9      ch:char;
 10      function min(x,y:longint):longint;
 11       begin
 12       if x<y then exit(x) else exit(y);
 13       end;
 14 procedure ins(x,y,z:longint);
 15  begin
 16  inc(tot);
 17  e[tot].from:=x;e[tot].go:=y;e[tot].v:=z;e[tot].next:=head[x];head[x]:=tot;
 18  end;
 19 procedure insert(x,y,z:longint);
 20  begin
 21  ins(x,y,z);ins(y,x,0);
 22  end;
 23 function bfs:boolean;
 24  var i,x,y:longint;
 25  begin
 26  fillchar(h,sizeof(h),0);
 27  l:=0;r:=1;q[1]:=s;h[s]:=1;
 28  while l<r do
 29   begin
 30   inc(l);
 31   x:=q[l];
 32   i:=head[x];
 33   while i<>0 do
 34    begin
 35    y:=e[i].go;
 36    if (e[i].v<>0) and (h[y]=0) then
 37     begin
 38      h[y]:=h[x]+1;
 39      inc(r);q[r]:=y;
 40     end;
 41    i:=e[i].next;
 42    end;
 43   end;
 44  exit (h[t]<>0);
 45  end;
 46 function dfs(x,f:longint):longint;
 47  var i,y,used,tmp:longint;
 48  begin
 49  if x=t then exit(f);
 50  used:=0;
 51  i:=cur[x];
 52  while i<>0 do
 53   begin
 54   y:=e[i].go;
 55   if (h[y]=h[x]+1) and (e[i].v<>0) then
 56    begin
 57    tmp:=dfs(y,min(e[i].v,f-used));
 58    dec(e[i].v,tmp);if e[i].v<>0 then cur[x]:=i;
 59    inc(e[i xor 1].v,tmp);
 60    inc(used,tmp);
 61    if used=f then exit(f);
 62    end;
 63   i:=e[i].next;
 64   end;
 65  if used=0 then h[x]:=-1;
 66  exit(used);
 67  end;
 68 procedure dinic;
 69  var i:longint;
 70  begin
 71  while bfs do
 72   begin
 73   for i:=s to t do cur[i]:=head[i];
 74   inc(maxflow,dfs(s,inf));
 75   end;
 76  end;
 77 procedure init;
 78  begin
 79  tot:=1;
 80  readln(n,m);
 81  for i:=1 to 2*n do
 82   begin
 83    inc(cnt);num[i,1]:=cnt;
 84    inc(cnt);num[i,2]:=cnt;
 85    inc(cnt);num[i,3]:=cnt;
 86    if i<=n then
 87     begin
 88     insert(num[i,3],num[i,1],inf);
 89     insert(num[i,3],num[i,2],m);
 90     end
 91    else
 92     begin
 93     insert(num[i,1],num[i,3],inf);
 94     insert(num[i,2],num[i,3],m);
 95     end;
 96   end;
 97  s:=0;t:=6*n+1;
 98  for i:=1 to n do
 99   begin
100    for j:=1 to n do
101     begin
102     read(ch);
103     if ch=‘Y‘ then insert(num[i,1],num[j+n,1],1)
104     else insert(num[i,2],num[j+n,2],1);
105     end;
106    readln;
107   end;
108  end;
109 procedure main;
110  begin
111  for i:=1 to n+1 do
112    begin
113    // for j:=1 to tot do if (e[j].go=t) or (e[j].from=t) then e[j].v:=0;
114     for j:=1 to 2*n do if j<=n then insert(s,num[j,3],1) else insert(num[j,3],t,1);
115     maxflow:=0;
116     dinic;
117     if maxflow<>n then break;
118    end;
119  writeln(i-1);
120  end;
121 begin
122  assign(input,‘input.txt‘);assign(output,‘output.txt‘);
123  reset(input);rewrite(output);
124  init;
125  main;
126  close(input);close(output);
127 end.