【题解】Luogu P4867 Gty的二逼妹子序列

原题传送门

同Luogu P4396 [AHOI2013]作业

询问多了10倍，但还能跑过（smog

#include <bits/stdc++.h>
#define N 100005
#define M 1000005
//#define getchar nc
using namespace std;
inline char nc(){
    static char buf[100000],*p1=buf,*p2=buf;
    return p1==p2&&(p2=(p1=buf)+fread(buf,1,100000,stdin),p1==p2)?EOF:*p1++;
}
inline int read()
{
    register int x=0,f=1;register char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9')x=(x<<3)+(x<<1)+ch-'0',ch=getchar();
    return x*f;
}
inline void write(register int x)
{
    if(!x)putchar('0');if(x<0)x=-x,putchar('-');
    static int sta[20];register int tot=0;
    while(x)sta[tot++]=x%10,x/=10;
    while(tot)putchar(sta[--tot]+48);
}
int n,m,blocksize=0,ans[M],v[N],p[N];
struct BinaryIndexTree{
    int tr[N];
    inline void update(register int pos,register int x)
    {
        for(register int i=pos;i<=n;i+=i&(-i))
            tr[i]+=x;
    }
    inline int query(register int pos)
    {
        int res=0;
        for(register int i=pos;i;i-=i&(-i))
            res+=tr[i];
        return res;
    }
}tr;
struct query{
    int l,r,a,b,id,bl;
}q[M];
inline bool cmp(register query a,register query b)
{
    return a.bl!=b.bl?a.l<b.l:((a.bl&1)?a.r<b.r:a.r>b.r);
}
inline void add(register int x)
{
    if(++p[v[x]]==1)
        tr.update(v[x],1);
}
inline void del(register int x)
{
    if(--p[v[x]]==0)
        tr.update(v[x],-1);
}
int main()
{
    n=read(),m=read();
    blocksize=sqrt(n);
    for(register int i=1;i<=n;++i)
        v[i]=read();
    for(register int i=1;i<=m;++i)
        q[i].l=read(),q[i].r=read(),q[i].a=read(),q[i].b=read(),q[i].id=i,q[i].bl=(q[i].l-1)/blocksize+1;
    sort(q+1,q+1+m,cmp);
    int l=1,r=0;
    for(register int i=1;i<=m;++i)
    {
        int ll=q[i].l,rr=q[i].r;
        while(l>ll)
            add(--l);
        while(l<ll)
            del(l++);
        while(r<rr)
            add(++r);
        while(r>rr)
            del(r--);
        ans[q[i].id]=tr.query(q[i].b)-tr.query(q[i].a-1);
    }
    for(register int i=1;i<=m;++i)
        write(ans[i]),puts("");
    return 0;
}