记录编号	22387	评测结果	AAAAAAAAAA
题目名称	494.YL杯超级篮球赛	最终得分	100
用户昵称	郭乾乐	是否通过	通过
代码语言	Pascal	运行时间	0.509 s
提交时间	2010-11-18 22:10:48	内存使用	1.73 MiB

program mwt;   
var  
    ans:extended;   
    a:array[0..50000,1..2]of extended;   
    key:array[1..50000]of longint;   
    w:array[1..50000]of extended;   
    n,i:longint;   
procedure sort(l,r,lab:longint);   
var  
    i,j,x,t:longint;   
begin  
    if l>=r then exit;   
    i:=l;j:=r;   
    x:=key[(l+r)shr 1];   
    repeat  
        while a[key[i],lab]<a[x,lab] do  
           i:=i+1;   
        while a[key[j],lab]>a[x,lab] do  
           j:=j-1;   
        if i<=j then  
          begin  
                t:=key[i];key[i]:=key[j];key[j]:=t;   
                i:=i+1;j:=j-1;   
           end;   
    until i>j;   
    sort(l,j,lab);   
    sort(i,r,lab);   
end;   
procedure jie(x:longint);   
var  
    i:longint;   
    l,r,sl,sr,min:extended;   
begin  
    for i:=1 to n do  
       key[i]:=i;   
    sort(1,n,x);   
    l:=0;r:=0;   
    sl:=0;sr:=0;   
    for i:=2 to n do  
       begin  
            sr:=sr+w[key[i]];   
           r:=r+(a[key[i],x]-a[key[1],x])*w[key[i]];   
      end;   
   min:=r;   
   for i:=2 to n do  
     begin  
         sl:=sl+w[key[i-1]];   
         l:=l+sl*(a[key[i],x]-a[key[i-1],x]);   
           r:=r-sr*(a[key[i],x]-a[key[i-1],x]);   
           sr:=sr-w[key[i]];   
           if l+r<min then min:=l+r;   
      end;   
   ans:=ans+min;   
end;   
begin  
    assign(input,'ballc.in');   
    reset(input);   
    assign(output,'ballc.out');   
    rewrite(output);   
    readln(n);   
    for i:=1 to n do  
      read(w[i]);   
    for i:=1 to n do  
      readln(a[i,1],a[i,2]);   
    ans:=0;   
    jie(1);   
    jie(2);   
    write(ans:0:2);   
    close(input);   
    close(output);   
end.