//-----------------------------------------------------------------------------
int binarySearchForFreePlace(
const FenwickTree& array_of_sums,
int left_border,
int right_border) {
// Left border inclusive, Right border not inclusive
if (right_border == 0 || array_of_sums.sum(left_border, right_border - 1) ==
right_border - left_border) {
return -2; // Later -2 + 1 -> -1
}
while (right_border - left_border > 1) {
int middle = left_border + (right_border - left_border) / 2;
if (array_of_sums.sum(middle, right_border - 1) ==
right_border - middle) {
right_border = middle;
continue;
}
if (array_of_sums.sum(left_border, middle - 1) ==
middle - left_border) {
left_border = middle;
continue;
}
right_border = middle;
}
return left_border;
}
rep(v, n)
{
int d = v + 1 - s, u = 0;
if(d > 0)
{
int i = cnt.find(d);
u = tot.sum(i) + (d - cnt.sum(i)) * (i + 1);
}
ans = min(ans, t + u);
for(auto x : ord[v]) s--, t -= x, cnt.add(x, 1), tot.add(x, x);
}
int main(int argc, char *argv[])
{
int A[MAXN + 16];
vector<int> AA;
for (int i = 1; i <= MAXN; i++)
{
A[i] = i;
AA.push_back(i);
}
FenwickTree ft;
ft.prepare(AA);
for (int i = 1; i <= MAXN; i++)
add(i, A[i]);
for (int cases = 1; cases <= 100; cases++) {
int L = rand() % MAXN + 1, R = rand() % MAXN + 1;
if (L > R) swap(L, R);
cout << "S[" << setw(4) << right << L << ", ";
cout << setw(4) << right << R << "] => ";
cout << get(R) - get(L - 1) << " = ";
cout << ft.sum(L - 1, R - 1);
cout << " = " << (R + L) * (R - L + 1) / 2 << '\n';
}
return 0;
}
int main ()
{
size_t n;
cin >> n;
FenwickTree tr (n);
int res = 0;
for (size_t i = 0; i < n; ++i)
{
int cur;
cin >> cur;
tr.modify (cur - 1, 1);
res += tr.sum (cur, n - 1);
}
cout << res;
return 0;
}
i64 sum(int pos){
return delta.sum(pos) * pos - delta_i.sum(pos);
}
