BZOJ 3668：起床困难综合症（贪心）

分析：按位贪心即可。

program sleep;
var
  a,g:array[..]of longint;
  n,i,m,ans,t,len,x,y,v:longint;
  c:char; s:string; e:boolean;
function cheak(x,y:longint):longint;
var i:longint;
begin
  for i:= to n do
   begin
     if g[i]= then x:=x and (a[i] shr (y-) and );
     if g[i]= then x:=x or (a[i]  shr (y-) and );
     if g[i]= then x:=x xor (a[i] shr (y-) and );
   end;
  exit(x);
end;
begin
   assign(input,'sleep.in');
reset(input);
assign(output,'sleep.out');
rewrite(output);
  readln(n,m);
  for i:= to n do
   begin
     readln(s); t:=pos(' ',s); c:=s[];
     if c='A' then g[i]:=;
     if c='O' then g[i]:=;
     if c='X' then g[i]:=;
     val(copy(s,t+,length(s)-t),a[i]);
   end;
   ans:=; e:=false;
   for i:= downto  do
    begin
      if cheak(,i)= then begin x:=; y:=; end
       else if cheak(,i)= then
        begin
          if (e=false)and(m shr (i-)=) then begin x:=; y:=; end
                else begin x:=; y:=; end;
        end
      else begin x:=; y:=; end;
      v:=v+x*( shl (i-));
      ans:=ans+y*( shl (i-));
      if v<m shr (i-) then e:=true;
    end;
   writeln(ans);
   close(input); close(output);
end.