呃，我不理解，为什么没人做

#include<cstdio>
#include<cmath>
#include<algorithm>
    using namespace std;
    const int maxn=50005,maxq=200005;
    int h[maxn],n,q,a[maxn],ans[maxq];
    struct data{
    int l,r,id;
    bool operator<(const data&b)const{
    if (h[l]==h[b.l]) return r<b.r;
    return l<b.l;
    }
    }que[maxq];
    inline int red(){
    int tot=0,f=1;char ch=getchar();
    while (ch<'0'||'9'<ch) {if (ch=='-') f=-f;ch=getchar();}
    while ('0'<=ch&&ch<='9') tot=tot*10+ch-48,ch=getchar();
    return tot*f;
    }
    void blocker(){
    int k=sqrt(n);
    for (int i=1;i<=n;i++) h[i]=(i-1)/k+1;
    }
    int L=0,R=0,now=0,hsh[1000005];
    void move(int x,int d){
    if (d==1){
    if (hsh[a[x]]==0) now++;
    hsh[a[x]]++;
    }else{
    hsh[a[x]]--;
    if (hsh[a[x]]==0) now--;
    }
 }
 int main(){
    n=red();
    for (int i=1;i<=n;i++) a[i]=red();
    blocker();
    q=red();
    for (int i=1;i<=q;i++) que[i].l=red(),que[i].r=red(),que[i].id=i;
    sort(que+1,que+1+q);
    for (int i=1;i<=q;i++){
    while (L<que[i].l) move(L++,-1);
    while (L>que[i].l) move(--L,1);
    while (R<que[i].r) move(++R,1);
    while (R>que[i].r) move(R--,-1);
    ans[que[i].id]=now;
    }
    for (int i=1;i<=q;i++) printf("%d\n",ans[i]);
    return 0;
 }