[BZOJ3631] [JLOI2014] 松鼠的新家

传送门

http://www.lydsy.com/JudgeOnline/problem.php?id=3631

题目大意

给定一棵无根树和一个序列，在这个序列上依次遍历，求每个点的访问次数(最后一个点的访问次数要-1)

题解

树剖

const
    maxn=300010;
var
    w:array[0..3*maxn,1..2]of longint;
    bite,fa,son,size,dep,top,pos,x:array[0..maxn]of longint;
    i,j,k:longint;
    n,m,len,a,b:longint;
procedure swap(var a,b:longint);
var c:longint;
begin c:=a; a:=b; b:=c; end;

procedure init(a,b:longint);
begin
    w[len,1]:=b;
    if w[a,2]=0 then w[a,2]:=len else w[w[a,1],2]:=len;
    w[a,1]:=len; inc(len);
end;

procedure dfs1(a:longint);
var tt,v:longint;
begin
    tt:=w[a,2]; size[a]:=1; v:=0;
    while tt<>0 do
        begin
            if w[tt,1]<>fa[a]
            then
                begin
                    fa[w[tt,1]]:=a; dep[w[tt,1]]:=dep[a]+1;
                    dfs1(w[tt,1]);
                    inc(size[a],size[w[tt,1]]); if size[w[tt,1]]>size[v] then v:=w[tt,1];
                end;
            tt:=w[tt,2];
        end;
    son[a]:=v;
end;

procedure dfs2(a,pre:longint);
var tt:longint;
begin
    tt:=w[a,2]; inc(len); pos[a]:=len; top[a]:=pre;
    if son[a]<>0 then dfs2(son[a],pre);
    while tt<>0 do
        begin
            if (w[tt,1]<>fa[a])and(w[tt,1]<>son[a]) then dfs2(w[tt,1],w[tt,1]);
            tt:=w[tt,2];
        end;
end;

procedure update(a,b:longint);
begin
    while a<=n+1 do
        begin
            inc(bite[a],b);
            inc(a,a and (-a));
        end;
end;

function query(a:longint):longint;
var ans:longint;
begin
    ans:=0;
    while a>0 do
        begin
            inc(ans,bite[a]);
            dec(a,a and (-a));
        end;
    exit(ans);
end;

procedure change(a,b:longint);
begin
    update(pos[b],-1); update(pos[b]+1,1);
    while top[a]<>top[b] do
        begin
            if dep[top[a]]then swap(a,b);
            update(pos[top[a]],1); update(pos[a]+1,-1);
            a:=fa[top[a]];
        end;
    if dep[a]>dep[b] then swap(a,b);
    update(pos[a],1); update(pos[b]+1,-1);
end;

begin
    readln(n); len:=n+1;
    for i:=1 to n do
        read(x[i]);
    for i:=1 to n-1 do
        begin readln(a,b); init(a,b); init(b,a); end;
    fa[1]:=0; dep[1]:=1; size[0]:=0;
    dfs1(1);
    len:=0;
    dfs2(1,1);
    for i:=1 to n-1 do
        change(x[i],x[i+1]);
    for i:=1 to n do
        writeln(query(pos[i]));
end.