【中山市选2008】小树

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Description

Input

Output

Sample Input
Input1:
1

Input2:
2
0 1 2

Input3:
3
0 1 1
0 2 2

Sample Output
Output1:
0.00

Output2:
2.00

Output3:
2.00

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解题思路

明显选两个点没有只选一个点优，直接将树遍历一遍，同时更新答案即可。

Codes:

var    n,ca,i,o,x,y,z:longint;    ans:real;    r,v:array[0..1000,0..1000]of longint;    bz:array[0..1000]of boolean;procedure insert(x,y,z:longint);begin    inc(r[x,0]);    r[x,r[x,0]]:=y;    v[x,r[x,0]]:=z;end;procedure dg(x,tot,value:longint);    var o:longint;begin    if tot<>0 then    begin        if value/tot>ans then ans:=value/tot;    end;    bz[x]:=false;    for o:=1 to r[x,0] do        if bz[r[x,o]] then            dg(r[x,o],tot+1,value+v[x,o])end;begin        ans:=0; read(n);        fillchar(r,sizeof(r),0);        fillchar(bz,sizeof(bz),true);        for i:=1 to n-1 do        begin            read(x,y,z);            insert(x,y,z);            insert(y,x,z);        end;        dg(0,0,0);        writeln(ans:0:2);end.