Pair Sum and Perfect Square

求 区间有多少

转换为二维数点

#pragma GCC optimize(2)
#pragma GCC optimize(3)


#include <bits/stdc++.h>
/*
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/hash_policy.hpp>
*/
using namespace std;

const double eps = 1e-10;
const double pi = 3.1415926535897932384626433832795;
const double eln = 2.718281828459045235360287471352;

#define f(i, a, b) for (int i = a; i <= b; i++)
#define scan(x) scanf("%d", &x)
#define mp make_pair
#define pb push_back
#define lowbit(x) (x&(-x))

#define fi first
#define se second
#define SZ(x) int((x).size())
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define summ(a) (accumulate(all(a), 0ll))

typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;

using ll=long long;

int tt,n=1e5,q,fk,a[(int)1e5+9],belong[(int)1e5+9],ans[(int)1e5+9],cnt[(int)1e5+9],sum,wz[(int)1e5+9]; 
vector<int> sq;
struct BIT
{
    vector<ll> a;
    int n;
    BIT(int x){
        n=x;
        a.resize(n+1);
        fill(a.begin(),a.end(),0ll);
    }
    void add(int x,int k){
        for(int i=x;i<=n;i+=lowbit(i))a[i]+=k;
    }

    ll query(int x){
        ll res=0ll;
        for(int i=x;i>0;i-=lowbit(i))res+=a[i];
        return res;
    }
};

void solve(){
    sum=0ll;
    cin>>n;
    BIT b(n);
    for(int i=1;i<=n;++i){
        cin>>a[i];
        cnt[i]=0,wz[a[i]]=i;
    }
    cin>>q;
    vector<array<int,2>> Q[(int)1e5+9];
    for(int i=1,x,y;i<=q;++i){
        ans[i]=0ll;
        cin>>x>>y;
        Q[y].push_back({y,i});
        Q[x-1].push_back({x-1,i});
        Q[x-1].push_back({y,-i});
        Q[y].push_back({x-1,-i});
    }
    //cerr<<"??\n";
    for(int i=0;i<=n;++i){
        if(i){
            for(auto it:sq){
                int x=it-a[i];
                if(x<=0)continue;
                if(wz[x]>=wz[a[i]])continue;
                if(x>n)break;
                b.add(wz[x],1);
            }
        }
       // cerr<<"??\n";
        for(auto [bb,cc]:Q[i]){
            if(cc>0){
                ans[cc]+=b.query(bb);
            }else ans[-cc]-=b.query(bb);
        }
       // cerr<<"!!!\n";
    }

    for(int i=1;i<=q;++i)cout<<ans[i]<<"\n";

}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    for(int i=1;i*i<=2*n-1;++i){
       sq.push_back(i*i);
    }
    //cerr<<sq.size();
    cin>>tt;

    while(tt--){
        solve();
    }
    //cout<<clock()*1.0/CLOCKS_PER_SEC<<endl;
    return 0;
}