Source Code
#include<bits/stdc++.h>
#include <unordered_map>
#include<unordered_set>
// Header files, namespaces,
// macros as defined above
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;

#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>

using namespace std;
#define _USE_MATH_DEFINES
# define M_PI           3.14159265358979323846  /* pi */
#define ll long long
#define ull unsigned long long
#define ld long double
#define vbe(v) ((v).begin()), ((v).end())
#define sz(v)     ((int)((v).size()))
#define prec(x)    cout<< fixed<< setprecision(x)
#define clr(v, d)   memset(v, d, sizeof(v))
#define rep(i, v)   for(int i=0;i<sz(v);++i)
#define lp(i, n)    for(int i=0;i<(int)(n);++i)
#define lpi(i, j, n)  for(int i=(j);i<(int)(n);++i)
#define lpd(i, j, n)  for(int i=(j);i>=(int)(n);--i)
#define MIN(x, y) (((x) < (y)) ? (x) : (y))
#define FASTIO ios_base::sync_with_stdio(false); cin.tie(NULL); cin.tie(0);
#define INFLL 1e18
#define INF 1e9
#define MOD 1000000007
#define MOD1 998244353
#define MAXN 200010
#define EPS 1e-6

ll GCD(ll a, ll b) { return (a) ? GCD(b % a, a) : b; }

ll LCM(ll a, ll b) { return a * b / GCD(a, b); }

ll fastpow(ll b, ll p) {
    if (!p) return 1;
    ll ret = fastpow(b, p >> 1);
    ret *= ret;
    if (p & 1) ret *= b;
    return ret;
}

int arr[MAXN];
ll vis[MAXN];

void solve(int tst) {
    int n;
    cin >> n;
    lp(i, n) {
        cin >> arr[i];
    }
    ll sum = 0;
    for (int z = 0; z < n; z++) {
        for (int i = 1; i * i <= arr[z]; i++) {
            if (arr[z] % i == 0) {
                int d1 = i;
                int d2 = arr[z] / i;
                int len1 = n - z;
                if (d1 == d2) {
                    ll xx = vis[d1];
                    sum += len1 * xx;
                } else {

                    ll xx = vis[d1];
                    sum += len1 * xx;
                    xx = vis[d2];
                    sum += len1 * xx;

                }
            }
        }

        vis[arr[z]] += z + 1;
    }
    lp(i, n)vis[arr[i]] = 0;
    cout << sum;
}

int main() {
    FASTIO;
    //freopen("circles.in", "r", stdin);
    int t = 1;
    cin >> t;
    lp(i, t) {
        solve(i + 1);
        cout << "\n";
    }
}
Copy
Powerful Inversions gaserashraf
GNU G++17
156 ms
1.5 MB
Accepted