#include using namespace std; using lint = long long; using pint = pair; using plint = pair; struct fast_ios { fast_ios() { cin.tie(nullptr), ios::sync_with_stdio(false), cout << fixed << setprecision(20); }; } fast_ios_; #define FOR(i, begin, end) for (int i = (begin), i##_end_ = (end); i < i##_end_; i++) #define IFOR(i, begin, end) for (int i = (end)-1, i##_begin_ = (begin); i >= i##_begin_; i--) #define REP(i, n) FOR(i, 0, n) #define IREP(i, n) IFOR(i, 0, n) #define ALL(x) (x).begin(), (x).end() // template void ndarray(vector& vec, const V& val, int len) { vec.assign(len, val); } template void ndarray(vector& vec, const V& val, int len, Args... args) { vec.resize(len), for_each(begin(vec), end(vec), [&](T& v) { ndarray(v, val, args...); }); } template bool chmax(T& m, const T q) { return m < q ? (m = q, true) : false; } template bool chmin(T& m, const T q) { return m > q ? (m = q, true) : false; } template pair operator+(const pair& l, const pair& r) { return make_pair(l.first + r.first, l.second + r.second); } template pair operator-(const pair& l, const pair& r) { return make_pair(l.first - r.first, l.second - r.second); } template vector srtunq(vector vec) { return sort(vec.begin(), vec.end()), vec.erase(unique(vec.begin(), vec.end()), vec.end()), vec; } template istream& operator>>(istream& is, vector& vec) { return for_each(begin(vec), end(vec), [&](T& v) { is >> v; }), is; } // output template ostream& dmpseq(ostream&, const T&, const string&, const string&, const string&); #if __cplusplus >= 201703L template ostream& operator<<(ostream& os, const tuple& tpl) { return apply([&os](auto&&... args) { ((os << args << ','), ...); }, tpl), os; } #endif // template ostream& operator<<(ostream& os, const pair& p) { return os << '(' << p.first << ',' << p.second << ')'; } template ostream& operator<<(ostream& os, const vector& x) { return dmpseq, T>(os, x, "[", ",", "]"); } template ostream& operator<<(ostream& os, const deque& x) { return dmpseq, T>(os, x, "deq[", ",", "]"); } template ostream& operator<<(ostream& os, const set& x) { return dmpseq, T>(os, x, "{", ",", "}"); } template ostream& operator<<(ostream& os, const unordered_set& x) { return dmpseq, T>(os, x, "{", ",", "}"); } template ostream& operator<<(ostream& os, const multiset& x) { return dmpseq, T>(os, x, "{", ",", "}"); } template ostream& operator<<(ostream& os, const map& x) { return dmpseq, pair>(os, x, "{", ",", "}"); } template ostream& operator<<(ostream& os, const unordered_map& x) { return dmpseq, pair>(os, x, "{", ",", "}"); } template ostream& dmpseq(ostream& os, const T& seq, const string& pre, const string& sp, const string& suf) { return os << pre, for_each(begin(seq), end(seq), [&](V x) { os << x << sp; }), os << suf; } template void print(const vector& x) { dmpseq, T>(cout, x, "", " ", "\n"); } #ifdef HITONANODE_LOCAL #define dbg(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ") " << __FILE__ << endl #else #define dbg(x) {} #endif template struct BIT : std::vector { BIT(int len = 0) : std::vector(len + 1) {} void reset() { fill(this->begin(), this->end(), 0); } void add(int pos, T v) { while (pos > 0 and pos < (int)this->size()) (*this)[pos] += v, pos += pos & -pos; } T sum(int pos) const { // (0, pos] T res = 0; while (pos > 0) res += (*this)[pos], pos -= pos & -pos; return res; } friend std::ostream &operator<<(std::ostream &os, const BIT &bit) { T prv = 0; os << '['; for (int i = 1; i < (int)bit.size(); i++) { T now = bit.sum(i); os << now - prv << ","; prv = now; } os << ']'; return os; } }; #include #include #include using namespace __gnu_pbds; // find_by_order(), order_of_key() template using pbds_set = tree, rb_tree_tag, tree_order_statistics_node_update>; template using pbds_map = tree, rb_tree_tag, tree_order_statistics_node_update>; int main() { int N, K; cin >> N >> K; vector A(N); cin >> A; vector A2I(N); REP(i, N) A2I[i] = plint(A[i], i); sort(ALL(A2I)); vector ii(N); REP(i, N) ii[A2I[i].second] = i + 1; BIT bit(N + 10); lint ret = A[K - 1]; set cur_set; set rightset; pbds_set all_set; FOR(i, K - 1, N) all_set.insert(pint(A[i], i)), bit.add(ii[i], A[i]); FOR(i, K - 1, 2 * (K - 1) + 1) if (i < N) cur_set.emplace(A[i], i); FOR(i, 2 * K - 1, N) rightset.emplace(A[i], i); for (lint m = 2; m * K <= N; m++) { if (cur_set.empty() or rightset.empty()) break; dbg(m); dbg(rightset); dbg(cur_set); lint cum = rightset.begin()->first + cur_set.begin()->first; int ir = rightset.begin()->second, ic = cur_set.begin()->second; all_set.erase(pint(A[ir], ir)); all_set.erase(pint(A[ic], ic)); bit.add(ii[ir], -A[ir]); bit.add(ii[ic], -A[ic]); dbg(cum); dbg(bit); if (int(all_set.size()) < m - 2) break; if (int(all_set.size()) > m - 3 and m >= 3) { auto p = *all_set.find_by_order(m - 3); cum += bit.sum(ii[p.second]); } chmin(ret, cum); all_set.insert(pint(A[ir], ir)); all_set.insert(pint(A[ic], ic)); bit.add(ii[ir], A[ir]); bit.add(ii[ic], A[ic]); const int l = (K - 1) * (m - 1); FOR(i, l, l + K - 1) { if (i >= N) break; bit.add(ii[i], -A[i]); cur_set.erase(pint(A[i], i)); all_set.erase(pint(A[i], i)); } FOR(i, l + K, l + K * 2 - 1) if (i < N) { cur_set.insert(pint(A[i], i)); } FOR(i, m * K - 1, (m + 1) * K - 1) { if (i >= N) break; rightset.erase(pint(A[i], i)); } } dbg(cur_set); dbg(rightset); dbg(bit); cout << ret << '\n'; }