树链剖分

不是树剖教程，是一些写码时候发现的问题

具体树剖教程可以参考博文https://www.cnblogs.com/chinhhh/p/7965433.html

 

 

#include<bits/stdc++.h>
#define ll long long
using namespace std;
const int N=1e5+11,M=2e5+11,tree_Sz=5e5+11,MAXX=1<<29;
int n,m,root;
ll p,a[N];
int to[M],nxt[M],edge,head[N];
int fa[N],dep[N],sz[N],son[N];
int top[N],cnt,seg[N],rev[N];

inline int read_int() {
    char ch=getchar(); int x=0,f=1;
    while(ch<'0' || ch>'9') { if(ch=='-') f=-1; ch=getchar(); }
    while('0'<=ch && ch<='9') x=(x<<1)+(x<<3)+ch-'0',ch=getchar();
    return x*f;
}

inline ll read_ll() {
    char ch=getchar(); ll x=0,f=1;
    while(ch<'0' || ch>'9') { if(ch=='-') f=-1; ch=getchar(); }
    while('0'<=ch && ch<='9') x=(x<<1)+(x<<3)+ch-'0',ch=getchar();
    return x*f;
}

struct SegmentTree {
    struct Node {
        ll val,tag;
    };
    Node t[tree_Sz];
    inline void pushup(int d) {
        t[d].val=(t[d<<1].val+t[d<<1|1].val)%p;
    }
    inline void pushdown(int d,int l,int r) {
        ll &tg=t[d].tag;
        if(!tg) return ;
        (t[d<<1].tag+=tg)%=p;
        (t[d<<1|1].tag+=tg)%=p;
        int mid=(l+r)>>1;
        (t[d<<1].val+=tg*(mid-l+1))%=p;
        (t[d<<1|1].val+=tg*(r-mid))%=p;
        tg=0;
    }
    void build(int d,int l,int r) {
        if(l==r) {
            t[d].val=a[rev[l]];
            return ;
        }
        int mid=(l+r)>>1;
        build(d<<1,l,mid);
        build(d<<1|1,mid+1,r);
        pushup(d);
    }
    inline void Build() {
        build(1,1,n);
    }
    void modify(int d,int l,int r,int x,int y,int z) {
        if(x<=l && r<=y) {
            (t[d].tag+=z)%=p;
            (t[d].val+=z*(r-l+1))%=p;
            return ;
        }
        pushdown(d,l,r);
        int mid=(l+r)>>1;
        if(x<=mid) modify(d<<1,l,mid,x,y,z);
        if(y>=mid+1) modify(d<<1|1,mid+1,r,x,y,z);
        pushup(d);
    }
    inline void Modify(int x,int y,ll z) {
        modify(1,1,n,x,y,z);
    }
    ll query(int d,int l,int r,int x,int y) {
        if(x<=l && r<=y) {
            return t[d].val;
        }
        pushdown(d,l,r);
        int mid=(l+r)>>1;
        ll res=0;
        if(x<=mid) (res+=query(d<<1,l,mid,x,y))%=p;
        if(y>=mid+1) (res+=query(d<<1|1,mid+1,r,x,y))%=p;
        return res;
    }
    inline ll Query(int x,int y) {
        return query(1,1,n,x,y);
    }
}st;

inline void addedge(int x,int y) {
    ++edge,to[edge]=y,nxt[edge]=head[x],head[x]=edge;
    ++edge,to[edge]=x,nxt[edge]=head[y],head[y]=edge;
}

void dfs1(int d,int f) {
    fa[d]=f,dep[d]=dep[f]+1,++sz[d];
    int maxx=0;
    for(int i=head[d];i;i=nxt[i]) {
        int u=to[i];
        if(u==f) continue;
        dfs1(u,d);
        sz[d]+=sz[u];
        if(sz[u]>maxx) maxx=sz[u],son[d]=u;
    }
}

void dfs2(int d) {
    if(son[d]) {
        int u=son[d];
        seg[u]=++cnt,rev[cnt]=u,top[u]=top[d];
        dfs2(u);
    }
    for(int i=head[d];i;i=nxt[i]) {
        int u=to[i];
        if(u==fa[d] || u==son[d]) continue;
        seg[u]=++cnt,rev[cnt]=u,top[u]=u;
        dfs2(u);
    }
}

inline void Update1(int x,int y,ll z) {
    int fx=top[x],fy=top[y];
    while(fx!=fy) {
        if(dep[fx]<dep[fy]) x^=y^=x^=y,fx^=fy^=fx^=fy;
        st.Modify(seg[fx],seg[x],z);
        x=fa[fx],fx=top[x];
    }
    if(dep[x]>dep[y]) x^=y^=x^=y;
    st.Modify(seg[x],seg[y],z);
}

inline void Update2(int x,ll z) {
    st.Modify(seg[x],seg[x]+sz[x]-1,z);
}

inline void Ask1(int x,int y) {
    int fx=top[x],fy=top[y];
    ll res=0;
    while(fx!=fy) {
        if(dep[fx]<dep[fy]) x^=y^=x^=y,fx^=fy^=fx^=fy;
        (res+=st.Query(seg[fx],seg[x]))%=p;
        x=fa[fx],fx=top[x];
    }
    if(dep[x]>dep[y]) x^=y^=x^=y;
    (res+=st.Query(seg[x],seg[y]))%=p;
    printf("%lld\n",res);
}

inline void Ask2(int x) {
    printf("%lld\n",st.Query(seg[x],seg[x]+sz[x]-1));
}

inline void print_test() {
    for(int i=0;i<=n;++i) cout<<setw(3)<<i; puts("");
    for(int i=0;i<=n;++i) cout<<setw(3)<<a[i]; puts("");
    for(int i=0;i<=n;++i) cout<<setw(3)<<fa[i]; puts("");
    for(int i=0;i<=n;++i) cout<<setw(3)<<dep[i]; puts("");
    for(int i=0;i<=n;++i) cout<<setw(3)<<sz[i]; puts("");
    for(int i=0;i<=n;++i) cout<<setw(3)<<son[i]; puts("");
    for(int i=0;i<=n;++i) cout<<setw(3)<<top[i]; puts("");
    for(int i=0;i<=n;++i) cout<<setw(3)<<seg[i]; puts("");
    for(int i=0;i<=n;++i) cout<<setw(3)<<rev[i]; puts("");
}

int main()
{
    int op,x,y; ll z;
    n=read_int(),m=read_int(),root=read_int(),p=read_ll();
    for(int i=1;i<=n;++i) a[i]=read_ll();
    for(int i=1;i<=n-1;++i) x=read_int(),y=read_int(),addedge(x,y);
    dfs1(root,0);
    seg[root]=++cnt,rev[cnt]=root,top[root]=root;
    dfs2(root);
    st.Build();

//    print_test();

    for(int i=1;i<=m;++i) {
        op=read_int();
        if(op==1) x=read_int(),y=read_int(),z=read_ll(),Update1(x,y,z);
        else if(op==2) x=read_int(),y=read_int(),Ask1(x,y);
        else if(op==3) x=read_int(),y=read_ll(),Update2(x,y);
        else x=read_int(),Ask2(x);
    }
    return 0;
}