1 program duipaixu2;
 2 type
 3         arr=array[1..10001] of longint;
 4 var
 5         x:arr;
 6         i,j,j1,n:longint;
 7         bool:boolean;
 8         s,s1:int64;
 9 procedure heap(var x:arr;j,i:longint);【堆排序】
10 var
11         i2,t1:longint;
12 begin
13         t1:=x[i];
14         i2:=2*i;
15         while  i2<=j do
16         begin
17                 if (i2<=j) and (x[i2] > x[i2+1]) then i2:=i2+1;
18                 if t1 > x[i2] then
19                 begin
20                         x[i]:=x[i2];
21                         i:=i2;i2:=2*i;
22                 end
23                 else i2:=j+1;
24         end;
25         x[i]:=t1;
26 end;
27 {================== main =====================}
28 begin
29         assign(input,'hebin.in');
30         assign(output,'hebin.out');
31         reset(input);
32         rewrite(output);
33         read(n);
34         for i:=1 to n do
35                 read(x[i]);
36         x[n+1]:=maxlongint;
37         j:=n;
38         s:=0;
39         s1:=0;
40         for i:=n div 2 downto 1 do  【建立新堆】
41                         heap(x,n,i);
42         repeat
43                 bool:=true;
44                 if x[2]<=x[3] then
45                 begin
46                         s1:=x[1]+x[2];
47                         s:=s+s1;
48                 end
49                 else begin s1:=x[1]+x[3];s:=s+s1 end;
50                 j1:=j;
51                 dec(j);
52                 if j>1 then
53                 begin
54                         x[1]:=x[j1];
55                         x[j1]:=maxlongint; 【这一步很重要，否则会出现上文提到的结果】
56                         heap(x,j,1);　　　　【分两次筛】
57                         x[1]:=s1;
58                         heap(x,j,1);
59                 end;
60         until j=1;
61         write(s);
62         close(input);
63         close(output);
64 end.

By ZYT

12.10.05