[BZOJ1036] [ZJOI2008]树的统计Count

传送门

http://www.lydsy.com/JudgeOnline/problem.php?id=1036

题目大意

支持
1.单点修改
2.查询路径点权最大值
3.查询点权路径和

题解

树链剖分模板入门题

const    maxn=30010;type    data=record sum,max:longint; end;var    w:array[0..3*maxn,1..2]of longint;    seg:array[0..8*maxn,1..4]of longint; {seg[i,3]:sum; seg[i,4]:max}    pos,val,size,top,son,fa,dep:array[0..maxn]of longint;    i,j,k:longint;    n,m,len,a,b:longint;    cha,ch:char;function mmax(a,b:longint):longint;begin if a>b then exit(a) else exit(b); 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 build(a,l,r:longint);var mid:longint;begin    seg[a,1]:=l; seg[a,2]:=r; seg[a,3]:=0; seg[a,4]:=0;    if l=r then exit;    mid:=(l+r)>>1;    build(a<<1,l,mid); build(a<<1+1,mid+1,r);end;procedure update(a,b,c:longint);var mid:longint;begin    if seg[a,1]=seg[a,2] then begin seg[a,3]:=c; seg[a,4]:=c; exit; end;    mid:=(seg[a,1]+seg[a,2])>>1;    if b<=mid    then update(a<<1,b,c) else update(a<<1+1,b,c);    seg[a,3]:=seg[a<<1,3]+seg[a<<1+1,3]; seg[a,4]:=mmax(seg[a<<1,4],seg[a<<1+1,4]);end;function query(a,l,r:longint):data;var mid:longint; ans,t1,t2:data;begin    if (seg[a,1]=l)and(seg[a,2]=r) then begin ans.sum:=seg[a,3]; ans.max:=seg[a,4]; exit(ans); end;    mid:=(seg[a,1]+seg[a,2])>>1;    if r<=mid then exit(query(a<<1,l,r)) else    if l>mid then exit(query(a<<1+1,l,r))    else begin t1:=query(a<<1,l,mid); t2:=query(a<<1+1,mid+1,r); ans.sum:=t1.sum+t2.sum; ans.max:=mmax(t1.max,t2.max); exit(ans); end;end;procedure dfs1(a:longint); {size[],son[],fa[],dep[]}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); {top[],pos[]}var tt:longint;begin    tt:=w[a,2]; top[a]:=pre; inc(len); pos[a]:=len; update(1,len,val[a]);    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;function queryans(a,b:longint):data;var tt:longint; t1,ans:data;begin    ans.sum:=0; ans.max:=-maxlongint;    while top[a]<>top[b] do        begin            if dep[top[a]]<dep[top[b]] then begin tt:=a; a:=b; b:=tt; end;            t1:=query(1,pos[top[a]],pos[a]);            inc(ans.sum,t1.sum); ans.max:=mmax(ans.max,t1.max);            a:=fa[top[a]];        end;    if dep[a]>dep[b] then begin tt:=a; a:=b; b:=tt; end;    t1:=query(1,pos[a],pos[b]);    inc(ans.sum,t1.sum); ans.max:=mmax(ans.max,t1.max);    exit(ans);end;begin    readln(n); len:=n+1;    for i:=1 to n-1 do        begin            readln(a,b);            init(a,b); init(b,a);        end;    for i:=1 to n do        read(val[i]);    dep[1]:=1; fa[1]:=0; size[0]:=0;    dfs1(1);    build(1,1,n); len:=0;    dfs2(1,1);    readln(m);    for i:=1 to m do        begin            read(cha,ch);            case ch of            'H':begin readln(cha,cha,cha,cha,a,b); val[a]:=b; update(1,pos[a],b); end;            'S':begin readln(cha,cha,a,b); writeln(queryans(a,b).sum); end;            'M':begin readln(cha,cha,a,b); writeln(queryans(a,b).max); end;            end;        end;end.