[模板] 树链剖分

讲真 sublime挺好用的。

atom更吼

#include<iostream>
#include<cstdio>
#define int long long
using namespace std;

const int MAXN=1000005;

inline int rd(){
  int ret=0,f=1;char c;
  while(c=getchar(),!isdigit(c))f=c=='-'?-1:1;
  while(isdigit(c))ret=ret*10+c-'0',c=getchar();
  return ret*f;
}

int n,m,root,p;
int w[MAXN],data[MAXN];

struct Edge{
  int next,to;
}e[MAXN<<1];
int ecnt=1,head[MAXN];
inline void adde(int x,int y){
  e[++ecnt].next = head[x];
  e[ecnt].to = y;
  head[x] = ecnt;
}

#define mid ((l+r)>>1)
#define ls (cur<<1)
#define rs (cur<<1|1)
int val[MAXN],add[MAXN];
inline void pushup(int cur){val[cur]=val[ls]+val[rs];}
inline void pushdown(int cur,int l,int r){
  (add[ls]+=add[cur])%=p;
  (add[rs]+=add[cur])%=p;
  (val[ls]+=add[cur]*(mid-l+1))%=p;
  (val[rs]+=add[cur]*(r-mid))%=p;
  add[cur]=0;
}
void build(int cur,int l,int r){
  if(l==r) {val[cur]=data[l];return;}
  build(ls,l,mid);
  build(rs,mid+1,r);
  pushup(cur);
}
int query(int L,int R,int cur,int l,int r){
  if(L<=l&&r<=R) return val[cur]%p;
  pushdown(cur,l,r);
  int ret=0;
  if(L<=mid) ret+=query(L,R,ls,l,mid);
  if(mid <R) ret+=query(L,R,rs,mid+1,r);
  return ret;
}
void update(int L,int R,int cur,int l,int r,int w){
  if(L<=l&&r<=R){
    (add[cur]+=w)%=p;
    (val[cur]+=w*(r-l+1))%=p;
    return;
  }
  pushdown(cur,l,r);
  if(L<=mid) update(L,R,ls,l,mid,w);
  if(mid <R) update(L,R,rs,mid+1,r,w);
  pushup(cur);
}

int fa[MAXN],dep[MAXN],hs[MAXN],siz[MAXN];
void dfs1(int cur,int pre){
  fa[cur]=pre;dep[cur]=dep[pre]+1;siz[cur]=1;
  int mx=-1;
  for(int i=head[cur];i;i=e[i].next){
    int v=e[i].to;
    if(v==pre) continue;
    dfs1(v,cur);
    siz[cur]+=siz[v];
    if(siz[v]>mx){mx=siz[v];hs[cur]=v;}
  }
}
int top[MAXN],id[MAXN],tim;
void dfs2(int cur,int tp){
  id[cur]=++tim;top[cur]=tp;data[tim]=w[cur];
  if(hs[cur]) dfs2(hs[cur],tp);
  for(int i=head[cur];i;i=e[i].next){
    int v=e[i].to;
    if(v==fa[cur]||v==hs[cur]) continue;
    dfs2(v,v);
  }
}
int query_link(int x,int y){
  int ret=0;
  while(top[x]!=top[y]){
    if(dep[top[x]]<dep[top[y]]) swap(x,y);
    ret+=query(id[top[x]],id[x],1,1,n);
    ret%=p;x=fa[top[x]];
  }
  if(dep[x]>dep[y]) swap(x,y);
  ret+=query(id[x],id[y],1,1,n);ret%=p;
  return ret;
}
void update_link(int x,int y,int w){
  w%=p;
  while(top[x]!=top[y]){
    if(dep[top[x]]<dep[top[y]]) swap(x,y);
    update(id[top[x]],id[x],1,1,n,w);
    x=fa[top[x]];
  }
  if(dep[x]>dep[y]) swap(x,y);
  update(id[x],id[y],1,1,n,w);
}
int query_subTree(int x){
  return query(id[x],id[x]+siz[x]-1,1,1,n)%p;
}
void update_subTree(int x,int w){
  update(id[x],id[x]+siz[x]-1,1,1,n,w%p);
}

main(){
  n=rd();
  m=rd();
  root=rd();
  p=rd();
  for(int i=1;i<=n;i++)w[i]=rd();
  int x,y,z,q;
  for(int i=1;i<=n-1;i++){
    x=rd();
    y=rd();
    adde(x,y);
    adde(y,x);
  }
  dfs1(root,0);
  dfs2(root,root);
  build(1,1,n);
  for(int i=1;i<=m;i++){
    q=rd();
    switch(q){
      case 1:{
        x=rd();
        y=rd();
        z=rd();
        update_link(x,y,z%p);
        break;
      }
      case 2:{
        x=rd();
        y=rd();
        printf("%lld
",query_link(x,y));
        break;
      }
      case 3:{
        x=rd();
        y=rd();
        update_subTree(x,y);
        break;
      }
      case 4:{
        x=rd();
        printf("%lld
",query_subTree(x));
        break;
      }
    }
  }
  return 0;
}