132 lines
2.7 KiB
C++
132 lines
2.7 KiB
C++
/* Problem URL: https://cses.fi/problemset/task/1748 */
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#include <bits/stdc++.h>
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using namespace std;
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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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int n;
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cin >> n;
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map<int, int> var;
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vi fds(n);
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repv(i, fds) {
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cin >> i;
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var[i] = 0;
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}
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int v = 0;
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repv(i, var) {
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i.second = v;
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v++;
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}
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repv(i, fds) {
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i = var[i];
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}
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while (__builtin_popcount(fds.size()) != 1) {
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fds.push_back(0);
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}
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vl seg(fds.size() * 2);
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ll mod = 1e9 + 7;
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auto update = [&](int i, ll v) {
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seg[i + fds.size()] += v;
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seg[i + fds.size()] %= mod;
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for (i = (i + fds.size()) / 2; i > 0; i /= 2) {
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seg[i] = (seg[i * 2] + seg[i * 2 + 1]) % mod;
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}
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};
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function<ll(int, int, int, int, int)> search = [&](int i, int l, int r, int tl, int tr) -> ll {
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if (l > tr || r < tl) {
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return 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) / 2;
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return (search(i * 2, l, mid, tl, tr) + search(i * 2 + 1, mid + 1, r, tl, tr)) % mod;
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};
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rep(i, n) {
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ll tmp = search(1, 0, fds.size() - 1, 0, fds[i] - 1) + 1;
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update(fds[i], tmp);
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}
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cout << search(1, 0, n - 1, 0, n - 1) << '\n';
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}
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