P3178 [HAOI2015]树上操作

P3178 [HAOI2015]树上操作

思路

板子嘛，其实我感觉树剖没啥脑子
就是debug

代码

#include <bits/stdc++.h>
#define int long long
#define ll long long
#define ls rt<<1
#define rs rt<<1|1
#define FOR(i,a,b) for(int i=a;i<=b;++i)
using namespace std;
const int maxn=1e6+7;
int read() {
    int x=0,f=1;char s=getchar();
    for(;s>'9'||s<'0';s=getchar()) if(s=='-') f=-1;
    for(;s>='0'&&s<='9';s=getchar()) x=x*10+s-'0';
    return x*f;
}
int n,m,w[maxn];
int dep[maxn],son[maxn],fa[maxn],siz[maxn];
int a[maxn],idx[maxn],top[maxn],cnt;
struct node {
    int v,nxt;
}e[maxn<<1];
int head[maxn<<1],tot;
void add_edge(int u,int v) {
    e[++tot].v=v;
    e[tot].nxt=head[u];
    head[u]=tot;
}
namespace seg_tree {
    struct node {
        int l,r,siz;
        ll tot,lazy;
    }e[maxn<<2];
    void pushup(int rt) {
        e[rt].tot=e[ls].tot+e[rs].tot;
    }
    void pushdown(int rt) {
        if(e[rt].lazy) {
            e[ls].tot+=e[ls].siz*e[rt].lazy;
            e[rs].tot+=e[rs].siz*e[rt].lazy;
            e[ls].lazy+=e[rt].lazy;
            e[rs].lazy+=e[rt].lazy;
            e[rt].lazy=0;
        }
    }
    void build(int l,int r,int rt) {
        e[rt].l=l,e[rt].r=r,e[rt].siz=r-l+1;
        if(l==r) {
            e[rt].tot=a[l];
            return;
        }
        int mid=(l+r)>>1;
        build(l,mid,ls);
        build(mid+1,r,rs);
        pushup(rt);
    }
    void modify(int L,int R,int k,int rt) {
        if(L<=e[rt].l&&e[rt].r<=R) {
            e[rt].tot+=e[rt].siz*k;
            e[rt].lazy+=k;
            return;
        }
        pushdown(rt);
        int mid=(e[rt].l+e[rt].r)>>1;
        if(L<=mid) modify(L,R,k,ls);
        if(R>mid) modify(L,R,k,rs);
        pushup(rt);
    }
    ll query(int L,int R,int rt) {
        if(L<=e[rt].l&&e[rt].r<=R) return e[rt].tot;
        pushdown(rt);
        int mid=(e[rt].l+e[rt].r)>>1;
        ll ans=0;
        if(L<=mid) ans+=query(L,R,ls);
        if(R>mid) ans+=query(L,R,rs);
        return ans;
    }
}
void dfs1(int u,int f) {
    siz[u]=1;
    fa[u]=f;
    son[u]=0;
    dep[u]=dep[f]+1;
    for(int i=head[u];i;i=e[i].nxt) {
        int v=e[i].v;
        if(v==f) continue;
        dfs1(v,u);
        if(siz[v] > siz[son[u]]) son[u]=v;
        siz[u]+=siz[v];
    }
}
void dfs2(int u,int ttt) {
    idx[u]=++cnt;
    a[cnt]=w[u];
    top[u]=ttt;
    if(!son[u]) return;
    dfs2(son[u],ttt);
    for(int i=head[u];i;i=e[i].nxt) {
        if(!idx[e[i].v])
            dfs2(e[i].v,e[i].v);
    }
}
ll SUM(int x,int y) {// 路径
    ll ans=0;
    while(top[x]!=top[y]) {
        if(dep[top[x]]<dep[top[y]]) swap(x,y);
        ans+=seg_tree::query(idx[top[x]],idx[x],1);
        x=fa[top[x]];
    }
    if(dep[x]>dep[y]) swap(x,y);
    ans+=seg_tree::query(idx[x],idx[y],1);
    return ans;
}
main() {
    n=read(),m=read();
    FOR(i,1,n) w[i]=read();
    FOR(i,2,n) {
        int x=read(),y=read();
        add_edge(x,y);
        add_edge(y,x);
    }
    dfs1(1,0);
    dfs2(1,1);
    seg_tree::build(1,n,1);

    FOR(i,1,m) {
        int opt=read(),x=read(),a;
        if(opt==1) {
            a=read();
            seg_tree::modify(idx[x],idx[x],a,1);
        } else if(opt==2) {
            a=read();
            seg_tree::modify(idx[x],idx[x]+siz[x]-1,a,1);
        } else if(opt==3) {
            cout<<SUM(1,x)<<"\n";
        }
    }
    return 0;
}