9-25考试第三题解题报告（还是写了指针翻译神马的都是浮云感觉好久不说话连话都不会说了233333333QVO）

type
        link=^pnode;
        pnode=record
                w:longint;
                next:link;
        end;

        var
                a,root:array[0..1122] of longint;
                g:array[0..1100,0..1100] of longint;
                hash:array[0..1122] of boolean;
                list:array[0..1122] of link;
                n,min:longint;

        procedure init;
        begin
                assign(input,'badnews.in');
                assign(output,'badnew.out');
                reset(input);
                rewrite(output);
        end;

        procedure terminate;
        begin
                close(input);
                close(output);
                halt;
        end;

        procedure qsort(s,t:longint);
        var
                i,j,x,m:longint;
        begin
                m:=(s+t)>>1;
                x:=a[m];
                a[m]:=a[s];
                a[s]:=x;
                i:=s;
                j:=t;
                repeat
                        while (i<j) and (x>a[j]) do dec(j);
                        if i<j then begin a[i]:=a[j]; inc(i); end;
                        while (i<j) and (x<a[i]) do inc(i);
                        if i<j then begin a[j]:=a[i]; dec(j); end;
                until i=j;
                a[i]:=x;
                inc(i);
                dec(j);
                if i<t then qsort(i,t);
                if s<j then qsort(s,j);
        end;

        function dfs(i:longint):longint;
        var
                j,tot:longint;
                p,q:link;
                pd:boolean;
        begin
                pd:=true;
                p:=nil;
                for j:=1 to g[i][0] do
                begin
                        if not hash[g[i][j]]  then
                        begin
                                pd:=false;
                                hash[g[i][j]]:=true;
                                new(q);
                                q^.w:=dfs(g[i][j])+1;
                                q^.next:=p;
                                p:=q;
                        end;
                end;
                if pd then exit(1);
                tot:=0;
                while p<>nil do
                begin
                        inc(tot);
                        a[tot]:=p^.w;
                        p:=p^.next;
                end;
                qsort(1,tot);

                for j:=2 to tot do inc(a[j],j-1);
                dfs:=0;
                for j:=1 to tot do if a[j]>dfs then dfs:=a[j];
        end;

        procedure main;
        var
                i,x,min:longint;
        begin
                fillchar(list,sizeof(list),0);
                readln(n);
                for i:=2 to n do
                begin
                        readln(x);
                        inc(g[i][0]);
                        g[i][g[i][0]]:=x;
                        inc(g[x][0]);
                        g[x][g[x][0]]:=i;
                end;
                for i:=1 to n do
                begin
                        fillchar(hash,sizeof(hash),0);
                        hash[i]:=true;
                        root[i]:=dfs(i);
                end;

                min:=10000;
                for i:=1 to n do
                begin
                        if root[i]<min then min:=root[i];
                end;
                writeln(min);
                a[0]:=0;
                for i:=1 to n do
                begin
                        if root[i]=min then
                        begin
                                inc(a[0]);
                                a[a[0]]:=i;
                        end;
                end;

                for i:=1 to a[0]-1 do write(a[i],' ');
                writeln(a[a[0]]);
        end;


        begin
                init;
                main;
                terminate;
        end.

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