serial.pas

Magio牛的usaco源代码

{
PROG:serial
LANG:PASCAL
}

program serial;
var
  fin,fout:text;
  bully,minvictim,v:string;
  half,i:integer;
function count(s:string;x:char):integer;
  var
    i:integer;
  begin
    count:=0;
    for i:=1 to length(s) do
      if s[i]=x then inc(count);
  end;
function makestr(l:integer;c:char):string;
  var
    i:integer;
  begin
    makestr:='';
    for i:=1 to l do
      makestr:=makestr+c;
  end;
function victim(x:char):string;
  var
    p,i:integer;
    overflow:boolean;
  procedure plus(w:integer);
    begin
      if w=0 then begin
        overflow:=true;
        exit;
      end
      else if victim[w]='9' then begin
        victim[w]:='0';
        plus(w-1);
      end
      else
        inc(victim[w]);
    end;
  begin
    victim:=bully;
    p:=length(victim);
    while count(victim,x)<=half do begin
      if victim[p]>x then begin
        overflow:=false;
        plus(p-1);
        if overflow then begin
          victim:=makestr(length(victim),'9');
          exit;
        end;
      end;
      victim[p]:=x;
      dec(p);
    end;
    for i:=p+1 to p+count(victim,x)-half-1 do
      victim[i]:='0';
  end;
begin
  assign(fin,'serial.in');
  reset(fin);
  readln(fin,bully);
  close(fin);

  half:=length(bully) div 2;
  minvictim:=victim('0');
  for i:=1 to 9 do begin
    v:=victim(chr(48+i));
    if v<minvictim then minvictim:=v;
  end;

  assign(fout,'serial.out');
  rewrite(fout);
  writeln(fout,minvictim);
  close(fout);
end.