树链剖分

#include<cstdio>
#include<iostream>
#include<cstring>
using namespace std;
const int MAXM=1000010,MAXN=1000010;
struct Edge{
    int from,to,nxt;
}e[MAXM];
int head[MAXN],edgeCnt=0;
void addEdge(int u,int v){
    e[++edgeCnt].from=u;
    e[edgeCnt].to=v;
    e[edgeCnt].nxt=head[u];
    head[u]=edgeCnt;
}
int n;
int dep[MAXN],fa[MAXN],size[MAXN];
int son[MAXN];
void dfs1(int x){
    size[x]=1;
    dep[x]=dep[fa[x]]+1;
    for(int i=head[x];i;i=e[i].nxt){
        int v=e[i].to;
        if(v!=fa[x]){
            fa[v]=x;
            dfs1(v);
            size[x]+=size[v];
            if(size[v]>size[son[x]])son[x]=v;
        }
    }
}
int top[MAXN],id[MAXN],idCnt=0;
int initValue[MAXN],nowValue[MAXN];
void dfs2(int x){
    if(x==son[fa[x]])top[x]=top[fa[x]];
    else top[x]=x;
    id[x]=++idCnt;
    nowValue[idCnt]=initValue[x];
    if(son[x])dfs2(son[x]);
    for(int i=head[x];i;i=e[i].nxt){
        int v=e[i].to;
        if(v!=son[x]&&v!=fa[x]){
            dfs2(v);
        }
    }
}
struct node{
    int ls,rs;
    int lazy;
    long long sum;
}tr[MAXN];
int nodeCnt=0;
void insert(int &now,int l,int r,int ll,int rr,int x){
    if(!now)now=++nodeCnt;
    int b=min(r,rr)-max(l,ll)+1;
    tr[now].sum+=x*b;
    if(l>=ll&&r<=rr){
        tr[now].lazy+=x;
        return;
    }
    int mid=(l+r)>>1;
    if(ll<=mid)insert(tr[now].ls,l,mid,ll,rr,x);
    if(rr>mid)insert(tr[now].rs,mid+1,r,ll,rr,x);
}
long long query(int now,int l,int r,int ll,int rr){
    if(l>=ll&&r<=rr)return tr[now].sum;
    int mid=(l+r)>>1;
    if(tr[now].lazy){
        if(!tr[now].ls)tr[now].ls=++nodeCnt;
        tr[tr[now].ls].lazy+=tr[now].lazy;
        tr[tr[now].ls].sum+=(mid-l+1)*tr[now].lazy;
        if(!tr[now].rs)tr[now].rs=++nodeCnt;
        tr[tr[now].rs].lazy+=tr[now].lazy;
        tr[tr[now].rs].sum+=(r-mid)*tr[now].lazy;
        tr[now].lazy=0;
    }
    long long ans=0;
    if(ll<=mid)ans+=query(tr[now].ls,l,mid,ll,rr);
    if(rr>mid)ans+=query(tr[now].rs,mid+1,r,ll,rr);
    return ans;
}
int root=0;
void change(int u,int v,int w){
    while(top[u]!=top[v]){
        if(dep[top[u]]<dep[top[v]])swap(u,v);
        insert(root,1,n,id[top[u]],id[u],w);
        u=fa[top[u]];
    }
    if(dep[u]>dep[v])swap(u,v);
    insert(root,1,n,id[u],id[v],w);
}
int mod;
long long sum(int u,int v){
    long long ans=0;
    while(top[u]!=top[v]){
        if(dep[top[u]]<dep[top[v]])swap(u,v);
        ans+=query(root,1,n,id[top[u]],id[u]);
        u=fa[top[u]];
    }
    if(dep[u]>dep[v])swap(u,v);
    ans+=query(root,1,n,id[u],id[v]);
    return ans%mod;
}
int main(){
    int m,r;
    scanf("%d%d%d%d",&n,&m,&r,&mod);
    for(int i=1;i<=n;i++){
        scanf("%d",&initValue[i]);
    }
    for(int i=1;i<=n-1;i++){
        int u,v;
        scanf("%d%d",&u,&v);
        addEdge(u,v);
        addEdge(v,u);//双向 
    }
    dfs1(r);
    dfs2(r);
    for(int i=1;i<=n;i++){
        insert(root,1,n,id[i],id[i],nowValue[id[i]]);
    }
    for(int i=1;i<=m;i++){
        int opt,x,y,z;
        scanf("%d%d",&opt,&x);
        switch(opt){
            case 1:
                scanf("%d%d",&y,&z);
                change(x,y,z);
                break;
            case 2:
                scanf("%d",&y);
                printf("%lld\n",sum(x,y));
                break;
            case 3:
                scanf("%d",&z);
                insert(root,1,n,id[x],id[x]+size[x]-1,z);
                break;
            case 4:
                printf("%lld\n",query(root,1,n,id[x],id[x]+size[x]-1)%mod);
                break;
        }
    }
    return 0;
}