bzoj1455

学习了一下可合并堆的一种写法——左偏树
感觉左偏树是一种类似启发式的方法
学习左偏树后这题就水过去了

 var fa,l,r,a,d:array[..] of longint;
     v:array[..] of boolean;
     i,n,m,x,y,f:longint;
     ch:char;

 function getf(x:longint):longint;
   begin
     if fa[x]<>x then fa[x]:=getf(fa[x]);
     exit(fa[x]);
   end;

 procedure swap(var a,b:longint);
   var c:longint;
   begin
     c:=a;
     a:=b;
     b:=c;
   end;

 function merge(x,y:longint):longint;
   begin
     if x= then exit(y);
     if y= then exit(x);
     if a[x]>a[y] then swap(x,y);
     r[x]:=merge(r[x],y);
     if d[r[x]]>d[l[x]] then swap(l[x],r[x]);
     d[x]:=d[r[x]]+;  //d表示这个节点到最近的可插入节点的距离，根据左偏树性质易得
     exit(x);
   end;

 begin
   readln(n);
   for i:= to n do
   begin
     read(a[i]);
     fa[i]:=i;
   end;
   d[]:=-;
   readln(m);
   for i:= to m do
   begin
     read(ch);
     if ch='M' then
     begin
       readln(x,y);
       if v[x] or v[y] then continue;
       x:=getf(x);
       y:=getf(y);
       if x=y then continue;
       f:=merge(x,y);
       fa[x]:=f;
       fa[y]:=f;
     end
     else begin
       readln(x);
       if v[x] then
       begin
         writeln();
         continue;
       end;
       x:=getf(x);
       v[x]:=true;
       writeln(a[x]);
       fa[x]:=merge(l[x],r[x]);
       fa[fa[x]]:=fa[x];
     end;
   end;
 end.