小B的询问

#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;
#define ll long long
#define re register
const int N=50005;
void read(int &a)
{
    a=0;
    int d=1;
    char ch;
    while(ch=getchar(),ch>‘9‘||ch<‘0‘)
        if(ch==‘-‘)
            d=-1;
    a=ch^48;
    while(ch=getchar(),ch>=‘0‘&&ch<=‘9‘)
        a=(a<<3)+(a<<1)+(ch^48);
    a*=d;
}
struct note
{
    int l,r,pos,id;
    bool operator < (const note &x) const
    {
        if(x.pos==pos)
            return r>x.r;
        else
            return pos>x.pos;
    }
}a[N];
int b[N];
ll cnt[N],ANS[N];
int main()
{
    int n,m,k;
    read(n);
    read(m);
    read(k);
    int siz=sqrt(n);
    for(re int i=1;i<=n;i++)
        read(b[i]);
    for(re int i=1;i<=m;i++)
    {
        read(a[i].l);
        read(a[i].r);
        a[i].id=i;
        a[i].pos=(a[i].l-1)/siz+1;
    }
    sort(a+1,a+1+n);
    int l=n+1,r=n,ans=0;
    for(re int i=1;i<=m;i++)
    {
        while(l>a[i].l)
            l--,ans=ans+2*cnt[b[l]]+1,cnt[b[l]]++;
        while(r<a[i].r)
            r++,ans=ans+2*cnt[b[r]]+1,cnt[b[r]]++;
        while(l<a[i].l)
            ans=ans-2*cnt[b[l]]+1,cnt[b[l]]--,l++;
        while(r>a[i].r)
            ans=ans-2*cnt[b[r]]+1,cnt[b[r]]--,r--;
        ANS[a[i].id]=ans;
    }
    for(re int i=1;i<=m;i++)
        printf("%lld\n",ANS[i]);
    return 0;
}