树链剖分模板

最近好像掉进什么奇怪的数据结构坑里去了。。。。

先放个板子，讲解和例题到时候在补上

# include<cstring>
# include<iostream>
# include<cstdio>
# include<cmath>
# include<cstdio>
# include<algorithm>

using std::swap;
const int mn = 200005;

struct edge{int to,next;};
edge e[mn*2];
int head[mn],edge_max;
int n,m,r,mod;
int val[mn],w[mn];
int deep[mn],siz[mn],fa[mn];
int id[mn],bl[mn],tot;
struct tree{int l,r,sum,lazy;};
tree  tr[mn*4];
void add(int x,int y)
{
    e[++edge_max].to=y;
    e[edge_max].next=head[x];
    head[x]=edge_max;
}
void dfs1(int x)
{
    siz[x]=1;
    for(int i=head[x];i;i=e[i].next)
    {
        int u=e[i].to;
        if(u!=fa[x])
        {
            deep[u]=deep[x]+1;
            fa[u]=x;
            dfs1(u);
            siz[x]+=siz[u];
        }
    }
}
void dfs2(int x,int chain)
{
    int k=0;
    id[x]=++tot;
    w[tot]=val[x];
    bl[x]=chain;
    for(int i=head[x];i;i=e[i].next)
    {
        int u=e[i].to;
        if(deep[u]>deep[x] && siz[u]>siz[k])
            k=u;
    }
    if(!k)
        return ;
    dfs2(k,chain);
    for(int i=head[x];i;i=e[i].next)
    {
        int u=e[i].to;
        if(deep[u]>deep[x] && u!=k)
            dfs2(u,u);
    }
}
void build(int l,int r,int cur)
{
    tr[cur].l=l,tr[cur].r=r;
    if(l==r)
    {
        tr[cur].sum=(w[l])%mod;
        return ;
    }
    int mid=l+r>>1;
    build(l,mid,cur<<1);
    build(mid+1,r,cur<<1|1);
    tr[cur].sum=(tr[cur<<1].sum+tr[cur<<1|1].sum)%mod;
}
void pushdown(int cur)
{
    if(tr[cur].lazy!=0)
    {
        tr[cur<<1].sum=(tr[cur<<1].sum+(tr[cur<<1].r-tr[cur<<1].l+1)*tr[cur].lazy)%mod;
        tr[cur<<1|1].sum=(tr[cur<<1|1].sum+(tr[cur<<1|1].r-tr[cur<<1|1].l+1)*tr[cur].lazy)%mod;
        tr[cur<<1].lazy=(tr[cur<<1].lazy+tr[cur].lazy)%mod;
        tr[cur<<1|1].lazy=(tr[cur<<1|1].lazy+tr[cur].lazy)%mod;
        tr[cur].lazy=0;
    }
    return ;
}
void update(int cur,int L,int R,int x)
{
    if(tr[cur].l>R || tr[cur].r<L)
        return ;
    if(tr[cur].l>=L && tr[cur].r<=R)
    {
        tr[cur].sum=((tr[cur].r-tr[cur].l+1)*x+tr[cur].sum)%mod;
        tr[cur].lazy=(tr[cur].lazy+x)%mod;
        return ;
    }
    pushdown(cur);
    update(cur<<1,L,R,x);
    update(cur<<1|1,L,R,x);
    tr[cur].sum=(tr[cur<<1].sum+tr[cur<<1|1].sum)%mod;
}
void treeadd(int x,int y,int z)
{
    while(bl[x]!=bl[y])
    {
        if(deep[bl[x]]<deep[bl[y]])
            swap(x,y);
        update(1,id[bl[x]],id[x],z);
        x=fa[bl[x]];
    }
    if(deep[x]>deep[y])
       swap(x,y);
    update(1,id[x],id[y],z);
}
int query(int cur,int L,int R)
{
    if(tr[cur].l>=L && tr[cur].r<=R)
        return tr[cur].sum;
    if(tr[cur].l>R || tr[cur].r<L)
        return 0;
    pushdown(cur);
    int ans=0;
    ans=query(cur<<1,L,R);
    ans+=query(cur<<1|1,L,R);
    tr[cur].sum=(tr[cur<<1].sum+tr[cur<<1|1].sum)%mod;
    ans=ans%mod;
    return ans;
}
void treesum(int x,int y)
{
    int ret=0;
    while(bl[x]!=bl[y])
    {
        if(deep[bl[x]]<deep[bl[y]])
            swap(x,y);
        ret=(ret+query(1,id[bl[x]],id[x]))%mod;
        x=fa[bl[x]];
    }
    if(deep[x]>deep[y])
        swap(x,y);
    ret=(ret+query(1,id[x],id[y]))%mod;
    printf("%d
",ret);
}
int main()
{
   int x,y,opt,z;
   scanf("%d%d%d%d",&n,&m,&r,&mod);
   for(int i=1;i<=n;i++)
     scanf("%d",&val[i]);
   for(int i=1;i<n;i++)
   {
       scanf("%d%d",&x,&y);
       add(x,y),add(y,x);
   }
   deep[r]=1;
   dfs1(r);
   dfs2(r,r);
   build(1,n,1);
   for(int i=1;i<=m;i++)
   {
      scanf("%d%d",&opt,&x);
      if(opt==1)
      {
          scanf("%d%d",&y,&z);
          treeadd(x,y,z%mod);
      }
      else if(opt==2)
      {
          scanf("%d",&y);
          treesum(x,y);
      }
      else if(opt==3)
      {
          scanf("%d",&y);
          update(1,id[x],id[x]+siz[x]-1,y%mod);
      }
      else {
        printf("%d
",query(1,id[x],id[x]+siz[x]-1));
      }
   }
   return 0;
}