树链剖分

study from:

http://www.cnblogs.com/chinhhh/p/7965433.html

https://www.luogu.org/problemnew/show/P3384

#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>
#include <time.h>
#include <string>
#include <set>
#include <map>
#include <list>
#include <stack>
#include <queue>
#include <vector>
#include <bitset>
#include <ext/rope>
#include <algorithm>
#include <iostream>
using namespace std;
#define ll long long
#define minv 1e-6
#define inf 1e9
#define pi 3.1415926536
#define nl 2.7182818284
//const ll mod=1e9+7;//998244353
const int maxn=1e5+10;

struct node
{
    int d;
    node *next;
}*e[maxn];

ll mod,tag[maxn<<2],sum[maxn<<2];
int dep[maxn],siz[maxn],fa[maxn]={0},son[maxn],id[maxn],top[maxn],num=0,n;
bool vis[maxn]={0};
ll v[maxn],point_num=0,old_id[maxn];

void dfs1(int d,int deep)
{
    node *p=e[d];
    int maxson=0,dd;
    vis[d]=1;
    dep[d]=deep;
    siz[d]=1;
    while (p)
    {
        dd=p->d;
        if (!vis[dd])
        {
            fa[dd]=d;
            dfs1(dd,deep+1);
            siz[d]+=siz[dd];
            if (siz[dd]>maxson)
                son[d]=dd,maxson=siz[dd];
        }
        p=p->next;
    }
}

void dfs2(int d,int topd)
{
    id[d]=++num;
    top[d]=topd;
    old_id[num]=d;
    if (son[d]!=0)
    {
        dfs2(son[d],topd);
        node *p=e[d];
        int dd;
        while (p)
        {
            dd=p->d;
            if (dd!=fa[d] && dd!=son[d])
                dfs2(dd,dd);
            p=p->next;
        }
    }
}

void build(int index,int l,int r)
{
    tag[index]=0;
    if (l==r)
    {
//        scanf("%lld",&sum[index]);
        sum[index]=v[old_id[++point_num]];
//        sum[index]=sum[index]%mod;
    }
    else
    {
        int m=(l+r)>>1;
        build(index<<1,l,m);
        build(index<<1|1,m+1,r);
        sum[index]=(sum[index<<1]+sum[index<<1|1])%mod;
    }
}

void push_down(int index,int len)
{
    tag[index<<1]=(tag[index]+tag[index<<1])%mod;
    tag[index<<1|1]=(tag[index]+tag[index<<1|1])%mod;
    sum[index<<1]=(tag[index]*((len+1)>>1)+sum[index<<1])%mod;
    sum[index<<1|1]=(tag[index]*(len>>1)+sum[index<<1|1])%mod;
    tag[index]=0;
}

void update(int index,int l,int r,int x,int y,ll k)
{
    if (x<=l && r<=y)
    {
        sum[index]=(k*(r-l+1)+sum[index])%mod;
        tag[index]=(k+tag[index])%mod;
        return;
    }
    if (tag[index]!=0)
        push_down(index,r-l+1);
    int m=(l+r)>>1;
    if (x<=m)
        update(index<<1,l,m,x,y,k);
    if (m<y)
        update(index<<1|1,m+1,r,x,y,k);
    sum[index]=(sum[index<<1]+sum[index<<1|1])%mod;
}

ll query(int index,int l,int r,int x,int y)
{
    if (x<=l && r<=y)
        return sum[index];
    if (r<x || l>y)
        return 0;
    if (tag[index]!=0)
        push_down(index,r-l+1);
    int m=(l+r)>>1;
    return (query(index<<1,l,m,x,y)+query(index<<1|1,m+1,r,x,y))%mod;
}

void work1(int x,int y,ll k)
{
    while (top[x]!=top[y])
    {
        if (dep[top[x]]<dep[top[y]])
            swap(x,y);
        update(1,1,n,id[top[x]],id[x],k);
        x=fa[top[x]];
    }
    if (dep[x]<dep[y])
        swap(x,y);
    update(1,1,n,id[y],id[x],k);
}

ll work2(int x,int y)
{
    ll tot=0;
    while (top[x]!=top[y])
    {
        if (dep[top[x]]<dep[top[y]])    ///top!
            swap(x,y);
        tot=(tot+query(1,1,n,id[top[x]],id[x]))%mod;
        x=fa[top[x]];
    }
    if (dep[x]<dep[y])
        swap(x,y);
    tot=(tot+query(1,1,n,id[y],id[x]))%mod;
    return tot;
}

void work3(int x,ll k)
{
    update(1,1,n,id[x],id[x]+siz[x]-1,k);
}

ll work4(int x)
{
    return query(1,1,n,id[x],id[x]+siz[x]-1);
}

int main()
{
    node *p;
    int q,root,x,y,mode,i;
    ll k;
    scanf("%d%d%d%lld",&n,&q,&root,&mod);
    for (i=1;i<=n;i++)
        scanf("%lld",&v[i]);
    for (i=1;i<n;i++)
    {
        scanf("%d%d",&x,&y);
        p=(node*) malloc (sizeof(node));
        p->d=y;
        p->next=e[x];
        e[x]=p;

        p=(node*) malloc (sizeof(node));
        p->d=x;
        p->next=e[y];
        e[y]=p;
    }

    dfs1(root,0);
    dfs2(root,root);    ///two root
    build(1,1,n);

    while (q--)
    {
        scanf("%d",&mode);
        if (mode==1)
        {
            scanf("%d%d%lld",&x,&y,&k);
            work1(x,y,k);
        }
        else if (mode==2)
        {
            scanf("%d%d",&x,&y);
            printf("%lld
",work2(x,y));
        }
        else if (mode==3)
        {
            scanf("%d%lld",&x,&k);
            work3(x,k);
        }
        else
        {
            scanf("%d",&x);
            printf("%lld
",work4(x));
        }
    }
    return 0;
}
/*
5 100 2 10000000
0 0 0 0 0
1 2
1 5
3 1
4 1
1 5 4 1
1 2 5 1
2 4 5
*/