171 lines
3.6 KiB
C++
171 lines
3.6 KiB
C++
/* Problem URL: https://codeforces.com/contest/903/problem/D */
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#include <bits/stdc++.h>
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#include <ext/pb_ds/assoc_container.hpp>
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#include <ext/pb_ds/tree_policy.hpp>
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using namespace std;
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using namespace __gnu_pbds;
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template <class T, class comp = less<>>
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using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
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#define V vector
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#define rmin(a, b) a = min(a, b)
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#define rmax(a, b) a = max(a, b)
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#define rep(i, lim) for (int i = 0; i < (lim); i++)
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#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
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#define repv(i, v) for (auto &i : (v))
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#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
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#define sortv(v) sort(v.begin(), v.end())
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#define all(v) (v).begin(), (v).end()
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using vi = vector<int>;
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using vvi = vector<vi>;
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using vvvi = vector<vvi>;
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using vvvvi = vector<vvvi>;
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using ll = long long;
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using vl = vector<ll>;
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using vvl = vector<vl>;
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using vvvl = vector<vvl>;
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using vvvvl = vector<vvvl>;
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template<class v>
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auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
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os << vec[0];
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for (size_t i = 1; i < vec.size(); i++) {
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os << ' ' << vec[i];
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}
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os << '\n';
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return os;
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}
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template<class v>
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auto operator>>(istream &is, vector<v> &vec)->istream& {
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for (auto &i : vec) {
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is >> i;
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}
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return is;
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}
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template<class v>
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auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
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for (auto &i : vec) {
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os << i[0];
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for (size_t j = 1; j < i.size(); j++) {
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os << ' ' << i[j];
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}
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os << '\n';
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}
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return os;
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}
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template<class v>
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auto operator>>(istream &is, vector<vector<v>> &vec)->istream& {
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for (auto &i : vec) {
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for (auto &j : i) {
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is >> j;
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}
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}
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return is;
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}
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int main()
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{
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ios::sync_with_stdio(false);
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cin.tie(nullptr);
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#define int long long
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int n;
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cin >> n;
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map<ll, int> var;
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int v = 0;
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vl a(n);
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repv(i, a) {
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cin >> i;
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var[i] = 0;
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}
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vl inv(var.size());
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repv(i, var) {
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i.second = v;
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inv[v] = i.first;
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v++;
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}
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int size = v;
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if (size > 1) {
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size = 1 << (32 - __builtin_clz(size - 1));
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}
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V<pair<int, ll>> seg(size * 2);
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auto update = [&](int i) {
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i += size;
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seg[i].first++;
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seg[i].second += inv[i - size];
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for (i >>= 1; i > 0; i >>= 1) {
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seg[i] = {seg[i * 2].first + seg[i * 2 + 1].first, seg[i * 2].second + seg[i * 2 + 1].second};
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}
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};
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function<pair<int, ll>(int, int, int, int, int)> query = [&](int i, int l, int r, int tl, int tr) -> pair<int, ll> {
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if (l > tr || r < tl) {
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return {0, 0};
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}
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if (l >= tl && r <= tr) {
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return seg[i];
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}
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int mid = (l + r) >> 1;
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auto ans1 = query(i * 2, l, mid, tl, tr);
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auto ans2 = query(i * 2 + 1, mid + 1, r, tl, tr);
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return {ans1.first + ans2.first, ans1.second + ans2.second};
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};
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__int128 ans = 0;
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rep(i, n) {
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int act = var[a[i]];
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int upper = act + 1 + var.count(a[i] + 1);
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int lower = act - 1 - var.count(a[i] - 1);
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auto tmp = query(1, 0, size - 1, upper, v - 1);
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ans += (__int128)tmp.first * a[i] - tmp.second;
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tmp = query(1, 0, size - 1, 0, lower);
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ans += (__int128)tmp.first * a[i] - tmp.second;
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update(act);
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}
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bool isneg = ans < 0;
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bool iszero = ans == 0;
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if (isneg) {
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ans = -ans;
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}
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string act;
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while (ans > 0) {
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act.push_back((ans % 10) + '0');
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ans /= 10;
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}
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reverse(all(act));
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cout << (isneg ? "-" : "") << (iszero ? "0" : "") << act << '\n';
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}
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