4034: [HAOI2015]树上操作

4034: [HAOI2015]树上操作

链接

思路：

　　树链剖分。操作：单点修改，路径查询，子树修改。

代码：

 #include<cstdio>
 #include<algorithm>
 #include<cstring>
 #include<iostream>
 #include<cmath>
 #include<cctype>
 
 using namespace std;
 
 const int N = ;
 typedef long long LL;
 
 struct Edge{
     int to,nxt;
     Edge() {}
     Edge(int a,int b) {to = a,nxt = b;}
 }e[N<<];
 int head[N],tot;
 LL sum[N<<],tag[N<<],w[N],data[N];
 int pos[N],siz[N],son[N],bel[N],deth[N],fa[N];
 int tn;
 
 inline int read() {
     int x = ,f = ;char ch = getchar();
     for (; !isdigit(ch); ch=getchar()) if(ch=='-') f = -;
     for (; isdigit(ch); ch=getchar()) x = x*+ch-'';
     return x * f;
 }
 void add_edge(int u,int v) {
     e[++tot] = Edge(v,head[u]);head[u] = tot;
     e[++tot] = Edge(u,head[v]);head[v] = tot;
 }
 void dfs1(int u,int pa) {
     siz[u] = ;
     deth[u] = deth[pa] + ;
     fa[u] = pa;
     for (int i=head[u]; i; i=e[i].nxt) {
         int v = e[i].to;
         if (v==pa) continue;
         dfs1(v,u);
         siz[u] += siz[v];
         if (!son[u] || siz[son[u]]<siz[v]) son[u] = v;
     }
 }
 void dfs2(int u,int top) {
     bel[u] = top;
     pos[u] = ++tn;
     data[pos[u]] = w[u];
     if (!son[u]) return;
     dfs2(son[u],top);
     for (int i=head[u]; i; i=e[i].nxt) {
         int v = e[i].to;
         if (v==fa[u] || v==son[u]) continue;
         dfs2(v,v);
     }
 }
 
 #define lson l,mid,rt<<1
 #define rson mid+1,r,rt<<1|1
 
 void pushup(int rt) {
     sum[rt] = sum[rt<<] + sum[rt<<|];
 }
 void pushdown(int rt,int len) {
     if (tag[rt]) {
         sum[rt<<] += 1ll * tag[rt] * (len-len/);tag[rt<<] += tag[rt];
         sum[rt<<|] += 1ll * tag[rt] * (len/);tag[rt<<|] += tag[rt];
         tag[rt] = ;
     }
 }
 void build(int l,int r,int rt) {
     if (l==r) {
         sum[rt] = data[l];
         return ;
     }
     int mid = (l + r) / ;
     build (lson);
     build (rson);
     pushup(rt);
 }
 void update(int l,int r,int rt,int L,int R,LL x) {
     if (L <= l && r <= R) {
         sum[rt] += 1ll * (r - l + ) * x;
         tag[rt] += x;
         return ;
     }
     pushdown(rt,r-l+);
     int mid = (l + r) / ;
     if (L <= mid) update(lson,L,R,x);
     if (R > mid)  update(rson,L,R,x);
     pushup(rt);
 }
 LL query(int l,int r,int rt,int L,int R) {
     if (L <= l && r <= R) {
         return sum[rt];
     }
     int mid = (l + r) / ;
     LL ret = ;
     pushdown(rt,r-l+);
     if (L <= mid) ret += query(lson,L,R);
     if (R > mid)  ret += query(rson,L,R);
     return ret;
 }
 void Ask(int x,int y) {
     LL ans = ;
     while (bel[x] != bel[y]) {
         if (deth[bel[x]] < deth[bel[y]]) swap(x,y);
         ans += query(,tn,,pos[bel[x]],pos[x]);
         x = fa[bel[x]];
     }
     if (deth[x] < deth[y]) swap(x,y);
     ans += query(,tn,,pos[y],pos[x]);
     printf("%lld\n",ans);
 }
 int main() {
     int n = read(),m = read();
     for (int i=; i<=n; ++i) w[i] = read();
     for (int i=; i<n; ++i) {
         int u = read(),v = read();
         add_edge(u,v);
     }
     dfs1(,);
     dfs2(,);
     build(,tn,);
     LL a;
     while (m--) {
         int opt = read(),x = read();
         if (opt == ) {
             a = read();
             update(,tn,,pos[x],pos[x],a);
         }
         else if (opt==) {
             a = read();
             update(,tn,,pos[x],pos[x]+siz[x]-,a);
         }
         else Ask(x,);
     }
     return ;
 }