hdu 6162 Ch’s gift(主席树+树链剖分)

题意：

给出一棵树的链接方法，每个点都有一个数字，询问U-》V节点经过所有路径中l < = x < = r的数字和

思路：

维护一个主席树，对于每一个节点来说，都更新自己这个节点的一条链。建立轻重链找LCA，不难发现每一个u->v来说。

都是找root[u]+ root[v] -root[lca] -root[fa[lca]]。只是L,R的脚标要处理好，因为这个WA了好久。。

#include<bits/stdc++.h>using namespace std;const int N=100005;typedef long long ll;ll n,m,w[N],b[N];struct edge{    int to,next;} vec[N<<1];int head[N],tot;///???int root[N] ,chairtree,rnu;struct node{    int lc,rc;    ll sum;} ctree[N*20];void build(int &i,int l,int r){    ctree[++chairtree]=ctree[i];    i=chairtree;    ctree[i].sum=0;    if(l>=r)return ;    int m =((r-l)>>1)+l;    build(ctree[i].lc,l,m);    build(ctree[i].rc,m+1,r);}void update(int& i,int l,int r,int pos){    ctree[++chairtree]=ctree[i];    i=chairtree;    ctree[i].sum+=b[pos];    if(l>=r)    {        return ;    }    int m=((r-l)>>1)+l;    if(pos<=m)        update(ctree[i].lc,l,m,pos);    else        update(ctree[i].rc,m+1,r,pos);}ll result=0;ll query(int i,int nl,int nr,int l,int r ){    if(l>=nl&&r<=nr)        return ctree[i].sum;    int mid=(l+r)>>1;    ll ans=0;    if(nr>mid)        ans+=query(ctree[i].rc,nl,nr,mid+1,r);    if(nl<=mid)        ans+=query(ctree[i].lc,nl,nr,l,mid);    return ans;}///????void add(int u,int v){    vec[++tot].to=v,vec[tot].next=head[u],head[u]=tot;    vec[++tot].to=u,vec[tot].next=head[v],head[v]=tot;}int dep[N],fa[N],siz[N],son[N];void dfs1(int u,int f,int d){    dep[u]=d;    fa[u]=f;    siz[u]=1;    son[u]=0;    for(int i=head[u];i;i=vec[i].next)    {        int v=vec[i].to;        if(v==f) continue;        dfs1(v,u,d+1);        siz[u]+=siz[v];        if(siz[son[u]]<siz[v])            son[u]=v;    }}int tree[N],top[N] ,cnt;void dfs2(int u,int tp){    top[u]=tp,tree[u]=++cnt;//cnt???????  ?chairtree?????  ??????    update(root[u]=root[fa[u]],1,rnu,w[u]);    if(!son[u])        return ;    for(int i=head[u];i;i=vec[i].next)    {        int v=vec[i].to;        if(v==fa[u])            continue;        dfs2(v,v);    }}int Lca(int x,int y){    int fx=top[x],fy=top[y];    while(fx!=fy)    {        if(dep[fx]<dep[fy])            swap(x,y),swap(fx,fy);        x=fa[fx],fx=top[x];    }    if(dep[x]>dep[y])swap(x,y);    return x;}int ef1 (int l, int r, int num) {    // <= num    while(l <= r) {        int mid = (l+r) / 2;        if(b[mid] == num)            return mid;        else if(b[mid] < num) {            l = mid + 1;        }        else {            r = mid - 1;        }    }    return r;}int ef2 (int l, int r, int num) {    // >= num    while(l <= r) {        int mid = (l+r) / 2;        if(b[mid] == num)            return mid;        if(b[mid] < num) {            l = mid + 1;        }        else {            r = mid - 1;        }    }    return l;}int main(){    while(scanf("%lld%lld",&n,&m)!=EOF){    memset(top,0,sizeof(top));    memset(dep,0,sizeof(dep));    memset(fa,0,sizeof(fa));    memset(siz,0,sizeof(siz));    memset(son,0,sizeof(son));    memset(head,0,sizeof(head));    memset(tree,0,sizeof(tree));    memset(ctree,0,sizeof(ctree));    memset(b,0,sizeof(b));    memset(w,0,sizeof(w));    memset(vec,0,sizeof(vec));    tot=chairtree=0;    for(int i=1; i<=n; i++)    {        scanf("%lld",&w[i]);        b[i]=w[i];    }    for(int i=1; i< n; i++)    {        int u,v;        scanf("%d%d",&u,&v );        add(u,v);    }    fa[1]=0;    sort(b+1,b+n+1);    rnu = unique(b+1,b+n+1)-(b+1);    for(int i=1; i<=n; i++)        w[i]=lower_bound(b+1,b+rnu+1,w[i])-b;    build(root[0],1,rnu);    dfs1(1,0,1);    dfs2(1,1);    for(int i=1;i<=m;i++)    {        result=0;        int u,v,k,x,y;        int l,r;        scanf("%d%d%d%d",&u,&v,&x,&y);        l=lower_bound(b+1,b+1+rnu,x)-b;//        l = ef2(1, rnu, x);        r=lower_bound(b+1,b+1+rnu,y)-b;        if(b[r] > y) r--;//        r = ef1(1, rnu, y);        if(l==0&&r==0)        {            if(i!=1)            printf(" 0");            else printf("0");            continue;        }        int lca=Lca(u,v);        result=query(root[u],l,r,1,rnu);        result=result+query(root[v],l,r,1,rnu);        result=result-query(root[lca],l,r,1,rnu);        result=result-query(root[fa[lca]],l,r,1,rnu);        if(i!=1)            printf(" ");        printf("%lld",result);    }    printf("\n");    }    return 0;}