RQNOJ八月赛

拯救海文星

　 　 一开始写了二分，发现可能爆double，猜到次数高了以后-1附近比较安全，就写了个牛顿迭代，其实开extended，二分也可以A的说。

CONST FileName='';
      delta=0.000001;
      oo=1E308;
var   a:array[0..10000] of longint;
      b:array[0..10000] of int64;
      n,i:longint;
      x1,x2:double;
function f(x:double):double;
         var i:longint;
             temp:double;
         begin
         f:=a[0];temp:=x;
         for i:=1 to n do
           begin
           f:=f+a[i]*temp;
           temp:=temp*x*x;
           end;
         end;
function g(x:double):double;
         var i:longint;
             temp:double;
         begin
         g:=b[1];temp:=x*x;
         for i:=2 to n do
           begin
           g:=g+b[i]*temp;
           temp:=temp*x*x;
           end;
         end;
BEGIN
readln(n);
for i:=0 to n do
  read(a[i]);
for i:=1 to n do
  b[i]:=a[i]*(i<<1-1);
if n=0 then writeln(0)
       else begin
            write('1 ');
            x1:=-1;x2:=-1;
            repeat
              x1:=x2;
              x2:=x1-f(x1)/g(x1);
            until abs(x1-x2)<delta;
            writeln(x2:5:5);
            end;
END.