vj p1357

题目描述

此乃水题也！

既然如此，为何还要写这个题解呢？当然，他水了，我不能水，所以水题就用树来完成！

先建个排序二叉树，然后来个中序遍历，一样搞定！

速度很快！有图有真相：

代码如下

type
        link=^point;
        point=record
                l,r:link;
                da,t:longint;
        end;
var
        head:link;
procedure add(h:link;m:longint);
var
        t:link;
begin
        if m<h^.da then
                begin
                        if h^.l<>nil then
                                begin
                                        add(h^.l,m);
                                end
                        else
                                begin
                                        new(t);
                                        t^.l:=nil;t^.r:=nil;
                                        t^.da:=m;
                                        t^.t:=1;
                                        h^.l:=t;
                                end;
                end
        else
        if m=h^.da then inc(h^.t)
        else
        if m>h^.da then
                begin
                        if h^.r<>nil then
                                begin
                                        add(h^.r,m);
                                end
                        else
                                begin
                                        new(t);
                                        t^.l:=nil;t^.r:=nil;
                                        t^.da:=m;
                                        t^.t:=1;
                                        h^.r:=t;
                                end;
                end;
end;
procedure print(h:link);
begin
        if h<>nil then
                begin
                        print(h^.l);
                        writeln(h^.da,' ',h^.t);
                        print(h^.r);
                end;
end;
procedure init;
var
        n,i,a:longint;
begin
        new(head);head^.l:=nil;head^.r:=nil;
        readln(n);
        readln(a);head^.da:=a;head^.t:=1;
        for i:=2 to n do
                begin
                        readln(a);
                        add(head,a);
                end;
end;
begin
        init;
        print(head);
end.