INVCNT.cpp

#include <bits/stdc++.h>

using namespace std;

#define int long long int
#define ld long double
#define F first
#define S second
#define P pair<int, int>
#define pb push_back

// a INDEXING : 1 BASED
// tree INDEXING : 1 BASED
int a[100000];
int tree[100000] = {0};

void update(int index, int value, int n)
{
    while (index <= n)
    {
        tree[index] += value;
        index += (index & (-index));
    }
}

int query(int index)
{
    int ans = 0;
    while (index > 0)
    {
        ans += tree[index];
        index -= (index & (-index));
    }
    return ans;
}

int32_t main()
{
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    int t;
    cin >> t;
    while (t--)
    {
        int i, j, k, n, no_of_query, left, right, m, ans = 0, cnt = 0, sum = 0;

        // BUILD AND UPDATE
        {
            cin >> n;

            for (int i = 1; i <= n; ++i)
            {
                cin >> a[i];
            }

            int ans = 0;
            for (int i = n; i >= 1; i--)
            {
                // cout << ans << "------>";
                ans += query(a[i] - 1);
                // cout << ans << endl;

                // cout << endl;

                update(a[i], 1, n);
            }
            cout << ans << "---" << endl;
        }

        int tree[100000] = {0};

        // //QUERY
        // {
        //     cin >> no_of_query;
        //     while (no_of_query--) {
        //         cin >> left >> right;

        //         //QUERY(index-to-query)
        //         cout << query(right) - query(left - 1) << endl;
        //     }
        // }
    }
}