type arr=array[0..50000,1..5] of longint;
var a:arr;
    i,j,k,l,n,t,z,q:longint;
    v,tv:real;
    h:real;
    pv,nv:real;
function getvv(h:real;x:integer):real;
var s:integer;
    hh:real;
begin
  s:=a[x,4]*a[x,3];
  if h<a[x,1] then hh:=0
    else
      if h>a[x,5] then hh:=a[x,2]
        else
          hh:=h-a[x,1];
  getvv:=s*hh;
end;
function getv(h:real):real;
var i:integer;
    tv:real;
begin
  tv:=0;
  for i:=1 to n do
    tv:=tv+getvv(h,i);
  getv:=tv;
end;

function geth(x,y:real):real;
var i,j:longint;
    th,ttv:real;
begin
  th:=(x+y)/2;
  ttv:=getv(th);
  if abs(ttv-v)<=1e-8 then begin geth:=th;exit;end;
  if ttv>v then geth:=geth(x,th)
           else if ttv<v then geth:=geth(th,y);
end;
procedure qs(x,y:longint);
var i,j,t,tt:longint;
begin
  i:=x;j:=y;
  t:=a[i,5];
  a[0]:=a[i];
  while i<j do
  begin
    while (i<j) and (t<a[j,5]) do dec(j);
    if i<j then
     begin
       a[i]:=a[j];
       inc(i);
     end;
    while (i<j) and (a[i,5]<t) do inc(i);
    if i<j then
     begin
       a[j]:=a[i];
       dec(j);
     end;
  end;
  a[i]:=a[0];
  if i+1<y then qs(i+1,y);
  if x<i-1 then qs(x,i-1);
end;
{main}
begin
  readln(z);
  for q:=1 to z do
  begin
    readln(n);
    for i:=1 to n do
    begin
      readln(a[i,1],a[i,2],a[i,3],a[i,4]);
      a[i,5]:=a[i,1]+a[i,2];
    end;
    qs(1,n);
    readln(v);
    tv:=getv(a[n,5]);
    if tv<v then begin writeln('OVERFLOW');continue;end;
    pv:=0;
    for i:=1 to n-1 do
    begin
      nv:=getv(a[i,5]);
      if abs(nv-v)<=1e-8 then begin h:=a[i,5];break;end;
      if nv>v then begin h:=geth(a[i-1,5],a[i,5]);break;end;
    end;
    writeln(h:0:2);
  end;
end.
多问一点:这题的最优(标准)方法谁能讲一下,谢谢!!