[BZOJ3999] [TJOI2015]旅游

传送门

http://www.lydsy.com/JudgeOnline/problem.php?id=3999

题目大意

给定一棵树,树上有权值,要求支持
查询树上两点a—>b(有方向)间路径上max(xj−xi)且j到a的距离比i大
以及路径整体+c

题解

树链剖分+线段树合并
注意细节！！

const    maxn=50040;type    data=record    a1,a2,minn,maxx:longint; end;var    w:array[0..3*maxn,1..2]of longint;    x,fa,son,size,dep,top,pos:array[0..maxn]of longint;    seg:array[0..4*maxn,1..7]of longint;    i,j,k:longint;    n,m,len,a,b,c:longint;function max(a,b:longint):Longint;begin if a>b then exit(a) else exit(b); end;function min(a,b:longint):Longint;begin if a<b then exit(a) else exit(b); end;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 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; seg[a,5]:=0; seg[a,6]:=0; seg[a,7]:=0;    if l=r then exit;    mid:=(l+r)>>1;    build(a<<1,l,mid); build(a<<1+1,mid+1,r);end;procedure pushdown(a:longint);begin    if seg[a,1]=seg[a,2] then begin seg[a,5]:=0; exit; end;    inc(seg[a<<1,3],seg[a,5]); inc(seg[a<<1+1,3],seg[a,5]);    inc(seg[a<<1,4],seg[a,5]); inc(seg[a<<1+1,4],seg[a,5]);    inc(seg[a<<1,5],seg[a,5]); inc(seg[a<<1+1,5],seg[a,5]);    seg[a,5]:=0;end;procedure update(a,l,r,c:longint);var mid:longint;begin    if seg[a,5]<>0 then pushdown(a);    if (seg[a,1]=l)and(seg[a,2]=r) then begin inc(seg[a,3],c); inc(seg[a,4],c); inc(seg[a,5],c); exit; end;    mid:=(seg[a,1]+seg[a,2])>>1;    if r<=mid then update(a<<1,l,r,c) else    if l>mid then update(a<<1+1,l,r,c)    else begin update(a<<1,l,mid,c); update(a<<1+1,mid+1,r,c); end;    seg[a,3]:=min(seg[a<<1,3],seg[a<<1+1,3]);    seg[a,4]:=max(seg[a<<1,4],seg[a<<1+1,4]);    seg[a,6]:=max(max(seg[a<<1,6],seg[a<<1+1,6]),seg[a<<1,4]-seg[a<<1+1,3]);    seg[a,7]:=max(max(seg[a<<1,7],seg[a<<1+1,7]),seg[a<<1+1,4]-seg[a<<1,3])end;function query(a,l,r:longint):data;var mid:longint; t1,t2,ans:data;begin    if seg[a,5]<>0 then pushdown(a);    if (seg[a,1]=l)and(seg[a,2]=r) then begin ans.minn:=seg[a,3]; ans.maxx:=seg[a,4]; ans.a1:=seg[a,6]; ans.a2:=seg[a,7]; 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.minn:=min(t1.minn,t2.minn);            ans.maxx:=max(t1.maxx,t2.maxx);            ans.a1:=max(max(t1.a1,t2.a1),t1.maxx-t2.minn);            ans.a2:=max(max(t1.a2,t2.a2),t2.maxx-t1.minn);            exit(ans);        end;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; update(1,len,len,x[a]);    if son[a]<>0 then dfs2(son[a],pre);    while tt<>0 do        begin            if (w[tt,1]<>son[a])and(w[tt,1]<>fa[a]) then dfs2(w[tt,1],w[tt,1]);            tt:=w[tt,2];        end;end;procedure queryans(a,b,c:longint);var t1,t2,tt:data;begin    t1.maxx:=0; t1.minn:=maxlongint; t1.a1:=0; t1.a2:=0;        t2.maxx:=0; t2.minn:=maxlongint; t2.a1:=0; t2.a2:=0;    while top[a]<>top[b] do        begin            if dep[top[a]]>dep[top[b]]            then                begin                    tt:=query(1,pos[top[a]],pos[a]);                    t1.a1:=max(max(t1.a1,tt.a1),tt.maxx-t1.minn);                    t1.maxx:=max(t1.maxx,tt.maxx);                    t1.minn:=min(t1.minn,tt.minn);                    update(1,pos[top[a]],pos[a],c);                    a:=fa[top[a]];                end            else                begin                    tt:=query(1,pos[top[b]],pos[b]);                    t2.a2:=max(max(t2.a2,tt.a2),t2.maxx-tt.minn);                    t2.maxx:=max(t2.maxx,tt.maxx);                    t2.minn:=min(t2.minn,tt.minn);                    update(1,pos[top[b]],pos[b],c);                    b:=fa[top[b]];                end;                                            end;    if dep[a]<dep[b]    then        begin            tt:=query(1,pos[a],pos[b]);            t2.a2:=max(max(t2.a2,tt.a2),t2.maxx-tt.minn);            t2.maxx:=max(t2.maxx,tt.maxx);            t2.minn:=min(t2.minn,tt.minn);            writeln(max(max(t1.a1,t2.a2),t2.maxx-t1.minn));            update(1,pos[a],pos[b],c);        end    else        begin            tt:=query(1,pos[b],pos[a]);            t1.a1:=max(max(t1.a1,tt.a1),tt.maxx-t1.minn);            t1.maxx:=max(t1.maxx,tt.maxx);            t1.minn:=min(t1.minn,tt.minn);            writeln(max(max(t1.a1,t2.a2),t2.maxx-t1.minn));            update(1,pos[b],pos[a],c);        end;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; build(1,1,n); dfs2(1,1);    readln(m);    for i:=1 to m do        begin            readln(a,b,c);            queryans(a,b,c);        end;end.