// // Monge 最短路問題に関するアルゴリズム全集 // // verified // COLOCON 2018 Final C - スペースエクスプローラー高橋君 (for Monge CHT) // https://beta.atcoder.jp/contests/colopl2018-final-open/tasks/colopl2018_final_c // // AtCoder EDPC Z - Frog 3 (for simple LARSCH, LARSCH, monge CHT) // https://atcoder.jp/contests/dp/tasks/dp_z // // Codeforces Round 189 (Div. 1) C. Kalila and Dimna in the Logging Industry (for simple LARSCH, LARSCH, monge CHT) // https://codeforces.com/contest/319/problem/C // // yukicoder No.705 ゴミ拾い Hard (for simple LARSCH, LARSCH, monge CHT) // https://yukicoder.me/problems/no/705 // // ABC 218 H - Red and Blue Lamps (for Alien DP) // https://atcoder.jp/contests/abc218/tasks/abc218_h // // yukicoder No.952 危険な火薬庫 (for SMAWK + D-enum) // https://yukicoder.me/problems/no/952 // // Codeforces Round 438 (Div. 1 + Div. 2 combined) F. Yet Another Minimization Problem // 2-solutions (slide access Monotone Minima + D-enum, slide access simple LARSCH + Alien DP) // https://codeforces.com/contest/868/problem/F // // ABC 480 G - Zonal Score Minimization (for anti-Monge D&D SMAWK) // https://atcoder.jp/contests/abc480/tasks/abc480_g // #include using namespace std; //------------------------------// // Template //------------------------------// using ll = long long; using i128 = __int128_t; using u128 = __uint128_t; using pint = pair; using pll = pair; using tll = array; using fll = array; using vint = vector; using vll = vector; using dint = deque; using dll = deque; using vvint = vector>; using vvll = vector>; using vpll = vector>; template using min_priority_queue = priority_queue, greater>; template inline bool chmax(S &a, T b) { return (a < b ? a = b, 1 : 0); } template inline bool chmin(S &a, T b) { return (a > b ? a = b, 1 : 0); } template inline auto maxll(S a, T b) { return max(ll(a), ll(b)); } template inline auto minll(S a, T b) { return min(ll(a), ll(b)); } template auto max(const T &a) { return *max_element(a.begin(), a.end()); } template auto min(const T &a) { return *min_element(a.begin(), a.end()); } template auto argmax(const T &a) { return max_element(a.begin(), a.end()) - a.begin(); } template auto argmin(const T &a) { return min_element(a.begin(), a.end()) - a.begin(); } template auto accum(const vector &a) { return accumulate(a.begin(), a.end(), T()); } template auto accum(const deque &a) { return accumulate(a.begin(), a.end(), T()); } #define REP(i, a) for (long long i = 0; i < (long long)(a); i++) #define REP2(i, a, b) for (long long i = a; i < (long long)(b); i++) #define RREP(i, a) for (long long i = (a)-1; i >= (long long)(0); --i) #define RREP2(i, a, b) for (long long i = (b)-1; i >= (long long)(a); --i) #define EB emplace_back #define PF push_front #define PB push_back #define MP make_pair #define FI first #define SE second #define ALL(x) x.begin(), x.end() // input stream template istream& operator >> (istream &is, vector &P) { for (int i = 0; i < (int)P.size(); ++i) cin >> P[i]; return is; } template istream& operator >> (istream &is, deque &P) { for (int i = 0; i < (int)P.size(); ++i) cin >> P[i]; return is; } template istream& operator >> (istream &is, vector> &P) { for (int i = 0; i < (int)P.size(); ++i) cin >> P[i]; return is; } // output stream #define COUT(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl template ostream& operator << (ostream &s, const pair &P) { return s << '<' << P.first << ", " << P.second << '>'; } template ostream& operator << (ostream &s, const array &P) { return s << '<' << P[0] << "," << P[1] << '>'; } template ostream& operator << (ostream &s, const array &P) { return s << '<' << P[0] << "," << P[1] << "," << P[2] << '>'; } template ostream& operator << (ostream &s, const array &P) { return s << '<' << P[0] << "," << P[1] << "," << P[2] << "," << P[3] << '>'; } template ostream& operator << (ostream &s, const vector &P) { for (int i = 0; i < P.size(); ++i) { s << P[i] << endl; } return s; } template ostream& operator << (ostream &s, const vector &P) { for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s; } template ostream& operator << (ostream &s, const deque &P) { for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s; } template ostream& operator << (ostream &s, const vector> &P) { for (int i = 0; i < P.size(); ++i) { s << endl << P[i]; } return s << endl; } template ostream& operator << (ostream &s, const set &P) { for (auto it : P) { s << "<" << it << "> "; } return s; } template ostream& operator << (ostream &s, const multiset &P) { for (auto it : P) { s << "<" << it << "> "; } return s; } template ostream& operator << (ostream &s, const unordered_set &P) { for (auto it : P) { s << "<" << it << "> "; } return s; } template ostream& operator << (ostream &s, const map &P) { for (auto it : P) { s << "<" << it.first << "->" << it.second << "> "; } return s; } template ostream& operator << (ostream &s, const unordered_map &P) { for (auto it : P) { s << "<" << it.first << "->" << it.second << "> "; } return s; } //------------------------------// // Monge //------------------------------// // check whether N x M matrix f is Monge or not, in O(NM) template bool is_monge (int N, int M, const FUNC &f, bool upper_triangular = false, bool output_detail = true) { assert(N > 0 && M > 0); for (int i = 0; i + 1 < N; i++) { for (int j = (upper_triangular ? i+2 : 0); j + 1 < M; j++) { auto f00 = f(i, j), f01 = f(i, j + 1), f10 = f(i + 1, j), f11 = f(i + 1, j + 1); if (f00 + f11 > f10 + f01) { if (output_detail) { cout << "Not Monge! " << endl; cout << "f(" << i << ", " << j << ") = " << f(i, j) << ", "; cout << "f(" << i << ", " << j + 1 << ") = " << f(i, j + 1) << endl; cout << "f(" << i + 1 << ", " << j << ") = " << f(i + 1, j) << ", "; cout << "f(" << i + 1 << ", " << j + 1 << ") = " << f(i + 1, j + 1) << endl; } return false; } } } return true; } // check whether N x M matrix f is anti-Monge or not, in O(NM) template bool is_anti_monge (int N, int M, const FUNC &f, bool upper_triangular = false, bool output_detail = true) { assert(N > 0 && M > 0); for (int i = 0; i + 1 < N; i++) { for (int j = (upper_triangular ? i+2 : 0); j + 1 < M; j++) { auto f00 = f(i, j), f01 = f(i, j + 1), f10 = f(i + 1, j), f11 = f(i + 1, j + 1); if (f00 + f11 < f10 + f01) { if (output_detail) { cout << "Not anti-Monge! " << endl; cout << "f(" << i << ", " << j << ") = " << f(i, j) << ", "; cout << "f(" << i << ", " << j + 1 << ") = " << f(i, j + 1) << endl; cout << "f(" << i + 1 << ", " << j << ") = " << f(i + 1, j) << ", "; cout << "f(" << i + 1 << ", " << j + 1 << ") = " << f(i + 1, j + 1) << endl; } return false; } } } return true; } // Convex Hull Trick /* Func:Monge 性 or anti-Monge 性を仮定 - MIN: クエリ x の取りうる最小値 - MAX: クエリ x の取りうる最大値 (f_i(MAX) がオーバーフローしないように注意) - INF: 最大値 - insert (Func f_i): add f_i, O(log X) - query (x): min_i{ f_i(x) }, O(log X) */ template struct MongeCHT { using Func = function; struct IndexedFunc { Func f; int id; IndexedFunc(Func f, int id) : f(std::move(f)), id(id) {} T eval(T x) const { return f(x); }; }; struct Node { IndexedFunc func; unique_ptr left, right; explicit Node(IndexedFunc f) : func(std::move(f)) {} }; const T MIN, MAX, INF = numeric_limits::max() / 2; unique_ptr root; int next_id = 0; MongeCHT() {} MongeCHT(T MIN, T MAX, T INF = numeric_limits::max() / 2) : MIN(MIN), MAX(MAX), INF(INF) { assert(MIN <= MAX); } // insert void insert(unique_ptr &p, T low, T high, IndexedFunc &f) { if (!p) { p = make_unique(std::move(f)); return; } if (p->func.eval(low) <= f.eval(low) && p->func.eval(high) <= f.eval(high)) return; if (p->func.eval(low) >= f.eval(low) && p->func.eval(high) >= f.eval(high)) { p->func = std::move(f); return; } T mid = (low + high) / 2; if (p->func.eval(mid) > f.eval(mid)) swap(p->func, f); if (low == high) return; if (p->func.eval(low) >= f.eval(low)) insert(p->left, low, mid, f); else insert(p->right, mid + 1, high, f); } int insert(Func f) { int id = next_id++; IndexedFunc func(std::move(f), id); insert(root, MIN, MAX, func); return id; } void clear() { root.reset(); next_id = 0; } // query pair query(const unique_ptr& p, T low, T high, T x) const { if (!p) return {INF, -1}; pair res = {p->func.eval(x), p->func.id}; if (low == high) return res; T mid = (low + high) / 2; if (x <= mid) return min(res, query(p->left, low, mid, x)); else return min(res, query(p->right, mid + 1, high, x)); } pair query(T x) const { assert(MIN <= x && x <= MAX); return query(root, MIN, MAX, x); } }; // find shortest path on DAG with Monge cost, by Convex Hull Trick, O(N log N) // vertex: 0, 1, 2, ..., N // f(i, j) must be Monge template vector> MongeShortestPathByCHT(int N, const FUNC &f) { VAL INF = numeric_limits::max() / 2; vector> dp(N + 1, make_pair(numeric_limits::max() / 2, -1)); MongeCHT cht(1, N, INF); dp[0].first = 0; for (int i = 0; i < N; i++) { auto f2 = [&, i](int j) -> long long { return dp[i].first + f(i, j); }; cht.insert(f2); dp[i + 1] = cht.query(i + 1); }; return dp; } // find min_j f(i, j) for all i, by Monotone Minima, O(H + W log H) // f(i, j) must be monotone (argmin is not decreasing) // slide access OK template void MonotoneMinimaRec (int HL, int HR, int WL, int WR, const FUNC &f, vector> &res) { if (HR - HL <= 0) return; int HM = (HL + HR) / 2; res[HM].second = WL; for (int i = WL; i < WR; i++) { VAL val = f(HM, i); if (res[HM].first > val) res[HM] = make_pair(val, i); } MonotoneMinimaRec(HL, HM, WL, res[HM].second + 1, f, res); MonotoneMinimaRec(HM + 1, HR, res[HM].second, WR, f, res); } template vector> MonotoneMinima(int H, int W, const FUNC &f) { vector> res(H, make_pair(numeric_limits::max() / 2, -1)); MonotoneMinimaRec(0, H, 0, W, f, res); return res; } // find shortest path on DAG with monotone cost, by D&D Monotone Minima, O(N (log N)^2) // vertex: 0, 1, 2, ..., N // f(i, j) must be monotone (argmin is not decreasing) // slide access OK template vector> DDMonotoneMinima(int N, const FUNC &f) { vector> res(N + 1, make_pair(numeric_limits::max() / 2, -1)); res[0].first = VAL(0); auto f2 = [&](int i, int j) -> VAL { return res[j].first + f(j, i); }; auto rec = [&](auto &&rec, int left, int right) -> void { if (right - left <= 1) return; int mid = (left + right) / 2; rec(rec, left, mid); MonotoneMinimaRec(mid, right, left, mid, f2, res); rec(rec, mid, right); }; rec(rec, 0, N + 1); return res; } // find min_j f(i, j) for all i, by SMAWK, O(H + W) // f(i, j) must be totally monotone // slide access NG template void SMAWKRec (const vector &X, const vector &Y, const FUNC &f, vector> &res) { if (X.empty()) return; // Reduce Step vector X2, Y2; for (auto y : Y) { while (!Y2.empty()) { int py = Y2.back(), x = X[(int)Y2.size() - 1]; if (f(x, y) >= f(x, py)) break; Y2.pop_back(); } if (Y2.size() < X.size()) Y2.emplace_back(y); } // Recurse Step for (int i = 1; i < (int)X.size(); i += 2) X2.emplace_back(X[i]); SMAWKRec(X2, Y2, f, res); // Interpolate Step int p = 0; for (int i = 0; i < (int)X.size(); i += 2) { int lim = (i + 1 < (int)X.size() ? res[X[i + 1]].second : Y.back()), best = Y[p]; while (Y[p] < lim) { p++; if (f(X[i], Y[p]) < f(X[i], best)) best = Y[p]; } res[X[i]] = {f(X[i], best), best}; } } template vector> SMAWK(int H, int W, const FUNC &f) { if (H == 0) return {}; assert(W > 0); vector> res(H, make_pair(numeric_limits::max() / 2, -1)); vector X(H), Y(W); for (int i = 0; i < H; i++) X[i] = i; for (int j = 0; j < W; j++) Y[j] = j; SMAWKRec(X, Y, f, res); return res; } // find shortest path on DAG with totally monotone cost, by D&D SMAWK, O(N log N) // vertex: 0, 1, 2, ..., N // f(i, j) must be totally monotone template vector> DDSMAWK(int N, const FUNC &f) { vector> res(N + 1, make_pair(numeric_limits::max() / 2, -1)); vector> tmp(N + 1); res[0].first = VAL(0); auto f2 = [&](int i, int j) -> VAL { return res[j].first + f(j, i); }; auto rec = [&](auto &&rec, int left, int right) -> void { if (right - left <= 1) return; int mid = (left + right) / 2; vector X(right - mid), Y(mid - left); for (int i = mid; i < right; i++) X[i - mid] = i; for (int j = left; j < mid; j++) Y[j - left] = j; rec(rec, left, mid); SMAWKRec(X, Y, f2, tmp); for (auto x : X) if (tmp[x].first < res[x].first) res[x] = tmp[x]; rec(rec, mid, right); }; rec(rec, 0, N + 1); return res; } // find shortest path on DAG with anti-Monge cost, by D&D SMAWK, O(NK log N) // vertex: 0, 1, 2, ..., N // f(i, j) must be anti-Monge, j >= i + K template vector> antiMongeDDSMAWK(int N, const FUNC &f, int K = 1) { assert(K >= 1); const VAL INF = numeric_limits::max() / 4; vector> res(N + 1, make_pair(INF, -1)); vector> tmp(N + 1, {INF, -1}); res[0].first = VAL(0); auto relax = [&](int i, int j) -> void { if (i != 0 && res[i].second == -1) return; VAL val = res[i].first + f(i, j); if (val < res[j].first) res[j] = {val, i}; }; auto rec = [&](auto &&rec, int left, int right) -> void { if (right - left <= 1) return; int mid = (left + right) / 2, border = min(right, mid + K - 1); rec(rec, left, mid); for (int j = mid; j < border; j++) { for (int i = left; i < mid && i <= j - K; i++) relax(i, j); } if (border < right) { vector X, Y; for (int j = border; j < right; j++) X.push_back(j); for (int i = mid - 1; i >= left; i--) { if (i == 0 || res[i].second != -1) Y.push_back(i); } if (!Y.empty()) { vector cols(Y.size()); iota(cols.begin(), cols.end(), 0); auto f2 = [&](int j, int k) -> VAL { return res[Y[k]].first + f(Y[k], j); }; SMAWKRec(X, cols, f2, tmp); for (auto x : X) { if (tmp[x].first < res[x].first) res[x] = {tmp[x].first, Y[tmp[x].second]}; } } } rec(rec, mid, right); }; rec(rec, 0, N + 1); return res; } // noshi's simplified LARSCH // find shortest path from vertex 0 on DAG in O(N log N) // vertex: 0, 1, 2, ..., N, f(i, j) must be Monge // slide access OK template struct SimpleLARSCH { VAL INF = numeric_limits::max() / 2; int CNT_INF = numeric_limits::max() / 2; // results vector dp; vector cnt, prev; // solver (random access ver) template vector> solve(int N, const FUNC &f, bool minimize_cnt = true) { dp.assign(N + 1, INF); cnt.assign(N + 1, CNT_INF); prev.assign(N + 1, 0); dp[0] = 0, cnt[0] = 0; auto relax = [&](int l, int r) -> void { VAL val = dp[l] + f(l, r); int cn = cnt[l] + 1; if (dp[r] > val || (dp[r] == val && (minimize_cnt ? cn < cnt[r] : cn > cnt[r]))) { dp[r] = val; cnt[r] = cn; prev[r] = l; } }; auto rec = [&](auto &&rec, int l, int r) -> void { if (r - l <= 1) return; int m = (l + r) / 2; for (int k = prev[l]; k <= prev[r]; k++) relax(k, m); rec(rec, l, m); for (int k = l + 1; k <= m; k++) relax(k, r); rec(rec, m, r); }; if (N > 0) relax(0, N), rec(rec, 0, N); vector> res(N + 1, make_pair(numeric_limits::max() / 2, -1)); res[0].first = VAL(0); for (int i = 1; i <= N; i++) res[i] = {dp[i], prev[i]}; return res; } // solver (slide access ver) template vector> solve (int N, const STATE &ini, const ADD &add, const DEL &del, const GETCOST &get, bool minimize_cnt = true) { dp.assign(N + 1, INF); cnt.assign(N + 1, CNT_INF); prev.assign(N + 1, 0); dp[0] = 0, cnt[0] = 0; STATE win[2] = { ini, ini }; int cl[2] = {0, 0}, cr[2] = {0, 0}; auto move_cursor = [&](int c, int l, int r) { while (cr[c] < r) add(win[c], cr[c]++); while (cl[c] > l) add(win[c], --cl[c]); while (cr[c] > r) del(win[c], --cr[c]); while (cl[c] < l) del(win[c], cl[c]++); }; auto relax = [&](int c, int l, int r) { move_cursor(c, l, r); VAL val = dp[l] + get(win[c]); int cn = cnt[l] + 1; if (dp[r] > val || (dp[r] == val && (minimize_cnt ? cn < cnt[r] : cn > cnt[r]))) { dp[r] = val; cnt[r] = cn; prev[r] = l; } }; auto rec = [&](auto &&rec, int l, int r) -> void { if (r - l <= 1) return; int m = (l + r) / 2; for (int k = prev[l]; k <= prev[r]; k++) relax(0, k, m); rec(rec, l, m); for (int k = l + 1; k <= m; k++) relax(1, k, r); rec(rec, m, r); }; if (N > 0) relax(0, 0, N), rec(rec, 0, N); vector> res(N + 1, make_pair(numeric_limits::max() / 2, -1)); res[0].first = VAL(0); for (int i = 1; i <= N; i++) res[i] = {dp[i], prev[i]}; return res; } vector reconstruct() { int N = (int)dp.size() - 1; vector path; for (int v = N; v > 0; v = prev[v]) path.emplace_back(v); path.emplace_back(0); reverse(path.begin(), path.end()); return path; } }; // LARSCH, in O(N) // vertex: 0, 1, 2, ..., N, f(i, j) must be Monge template struct LARSCH { struct RowReduce; struct ColReduce; struct ColMap { const ColMap* parent = nullptr; const vector *v = nullptr; constexpr int mapping(int i) const { int x = (v ? (*v)[i] : i); return (parent ? parent->mapping(x) : x); } }; struct Eval { const FUNC *f = nullptr; long long a = 1, b = 0; // row = a * i + b const ColMap *cm = nullptr; constexpr VAL operator () (int i, int j) const { int i2 = int(a * i + b), j2 = (cm ? cm -> mapping(j) : j); return (*f)(i2, j2); } }; struct RowReduce { int N; Eval e; int cur_row = 0, state = 0; unique_ptr rec; constexpr RowReduce(int N_, const Eval &e_) : N(N_), e(e_) { int M = N / 2; if (M > 0) { Eval e2 = e; e2.a = e.a * 2, e2.b = e.a + e.b; rec = make_unique(M, e2); } } constexpr void reset() { cur_row = 0, state = 0; if (rec) rec->reset(); } int get_argmin() { int i = cur_row++; if (!(i & 1)) { int prev = state, next = (i + 1 == N ? N - 1 : rec->get_argmin()); state = next; int res = prev; for (int j = prev + 1; j <= next; j++) { if (e(i, res) > e(i, j)) res = j; } return res; } else { return (e(i, state) <= e(i, i) ? state : i); } } }; struct ColReduce { int N; Eval e; int cur_row = 0; vector cols; ColMap cm; RowReduce rec; constexpr ColReduce(int N_, const Eval &e_) : N(N_), e(e_), cols(), cm{e.cm, &cols}, rec(N_, Eval{e.f, e.a, e.b, &cm}) { cols.reserve(N); } constexpr void reset() { cur_row = 0; cols.clear(); rec.reset(); } constexpr void push_col(int i, int j) { while (!cols.empty()) { int siz = (int)cols.size(); if (siz == i) break; int last = cols.back(); if (e(siz - 1, last) > e(siz - 1, j)) cols.pop_back(); else break; } if ((int)cols.size() != N) cols.emplace_back(j); } constexpr int get_argmin() { int i = cur_row++; if (i == 0) { cols.clear(); cols.emplace_back(0); } else { push_col(i, i * 2 - 1); push_col(i, i * 2); } return cols[rec.get_argmin()]; } }; FUNC f; ColMap root_cm; Eval root_eval; unique_ptr base; explicit LARSCH(int N_, const FUNC &f_) : f(std::move(f_)), root_cm{nullptr, nullptr}, root_eval{&f, 1, 0, &root_cm} { base = make_unique(N_, root_eval); } constexpr void reset() { base->reset(); } constexpr int get_argmin() { return base->get_argmin(); } }; // Monge Shortest Path Wrapper template struct MongeShortestPath { VAL INF = numeric_limits::max() / 2; int CNT_INF = numeric_limits::max() / 2; // results vector dp; vector cnt, prev; // solver (random access ver) template vector> solve(int N, const FUNC &f , const string solver = "simple_larsch") { vector> res(N + 1, make_pair(numeric_limits::max() / 2, -1)); if (solver == "simple_larsch") { SimpleLARSCH slar; res = slar.solve(N, f, true); dp = slar.dp, cnt = slar.cnt, prev = slar.prev; } else if (solver == "larsch") { dp.assign(N + 1, INF); cnt.assign(N + 1, CNT_INF); prev.assign(N + 1, 0); dp[0] = 0, cnt[0] = 0; auto f2 = [&](int i, int j) -> VAL { i++; if (i <= j) return INF; else return dp[j] + f(j, i); }; LARSCH lar(N, f2); for (int r = 1; r <= N; r++) { int l = lar.get_argmin(); dp[r] = dp[l] + f(l, r); prev[r] = l; cnt[r] = cnt[l] + 1; } res[0].first = VAL(0); for (int r = 1; r <= N; r++) res[r] = {dp[r], prev[r]}; } else if (solver == "monotone") { res = DDMonotoneMinima(N, f); } else if (solver == "smawk") { res = DDSMAWK(N, f); } else if (solver == "cht") { res = MongeShortestPathByCHT(N, f); } else { cout << "no solver" << endl; assert(true); } return res; } // solver (slide access ver) template vector> solve (int N, const STATE &ini, const ADD &add, const DEL &del, const GETCOST &get , const string solver = "simple_larsch") { vector> res; if (solver == "simple_larsch") { SimpleLARSCH sl; res = sl.solve(N, ini, add, del, get, true); dp = sl.dp, cnt = sl.cnt, prev = sl.prev; } else { cout << "no solver" << endl; assert(true); } return res; } vector reconstruct() { int N = (int)dp.size() - 1; vector path; for (int v = N; v > 0; v = prev[v]) path.emplace_back(v); path.emplace_back(0); reverse(path.begin(), path.end()); return path; } }; // find the d-edges shortest path for d = 1, 2, ..., D, in O(ND) // vertex: 0, 1, 2, ..., N // you can choose SMAWK (random access) or Monotone Minima (slide access) template struct MongeShortestPathWithDEdges { VAL INF = numeric_limits::max() / 2; // solver template vector solve(int N, const FUNC &f, int D, const string &solver = "smawk") { assert(D <= N); vector res{VAL(0)}, dp(N + 1, INF); dp[0] = 0; auto f2 = [&](int i, int j) -> VAL { return (j < i ? dp[j] + f(j, i) : INF); }; for (int d = 1; d <= D; d++) { vector> tmp; if (solver == "smawk") tmp = SMAWK(N + 1, N + 1, f2); else if (solver == "monotone") tmp = MonotoneMinima(N + 1, N + 1, f2); for (int i = d; i <= N; i++) dp[i] = tmp[i].first; res.emplace_back(dp[N]); } return res; } }; /* Alien's Trick (by ラグランジュ緩和) min_{x}: f(x) s.t. g(x) = K = max_{λ は整数}: min_{x} (f(x) + λ(g(x) - K)) max_{x}: f(x) s.t. g(x) = K = min_{λ は整数}: max_{x} (f(x) + λ(g(x) - K)) 【仮定】   ・f(x), g(x): 0 以上の整数値をとる関数   ・K: 整数   ・g(x) = p となる x についての f(x) の最小値を h(p) とおくと、h(p) は p について下に凸な関数   ・h(K) < ∞ (g(x) = K となる x が存在) 【インターフェース】   ・lag(λ): x✳︎ = argmin_{x} {f(x) + λ(g(x) - K)} としたときのペア値 {f(x✳︎), g(x✳︎)} を返す関数   ・返り値: {最適値, そのときの λ} */ template struct AliensTrick { // find lo such that g(lo) >= R template tuple find_low(const FUNC &lag, VAL R) { auto [f0, g0] = lag(VAL(0)); VAL lo = 0, hi = 0, flo = f0, glo = g0; if (glo >= R) return tie(lo, flo, glo); lo = VAL(-1); tie(flo, glo) = lag(lo); while (glo < R) { assert(lo < hi); VAL dif = hi - lo; hi = lo, lo -= VAL(2) * dif; tie(flo, glo) = lag(lo); } return tie(lo, flo, glo); } // find hi such that g(hi) <= L template tuple find_high(const FUNC &lag, VAL L) { auto [f0, g0] = lag(VAL(0)); VAL lo = 0, hi = 0, fhi = f0, ghi = g0; if (ghi <= L) return tie(hi, fhi, ghi); hi = VAL(1); tie(fhi, ghi) = lag(hi); while (ghi > L) { assert(lo < hi); VAL dif = hi - lo; lo = hi, hi += VAL(2) * dif; tie(fhi, ghi) = lag(hi); } return tie(hi, fhi, ghi); } // solver template pair solve(const FUNC &lag, VAL K) { // zero check auto [f0, g0] = lag(VAL(0)); if (g0 == K) return {f0, VAL(0)}; // find an initial value of binary search (by doubling) auto [lo, flo, glo] = find_low(lag, K); auto [hi, fhi, ghi] = find_high(lag, K); if (glo == K) return {flo, lo}; if (ghi == K) return {fhi, hi}; assert(glo > K && ghi < K); // binary search while (hi - lo > VAL(1)) { VAL mid = (lo + hi) / 2; auto [fmid, gmid] = lag(mid); if (gmid == K) return {fmid, mid}; if (gmid > K) lo = mid, flo = fmid, glo = gmid; else hi = mid, fhi = fmid, ghi = gmid; } // in case: h(p) has a collinear part (= could not achieve g(x) = K) // return the Lagrange value VAL reslo = flo + lo * (glo - K), reshi = fhi + hi * (ghi - K); if (reslo >= reshi) return {reslo, lo}; else return {reshi, hi}; } template pair minimize(const FUNC &lag, VAL K) { return solve(lag, K); } template pair maximize(const FUNC &lag, VAL K) { auto reverse_lag = [&](VAL lambda) -> pair { auto [f, g] = lag(-lambda); return {-f, g}; }; auto [f, g] = solve(reverse_lag, K); return {-f, -g}; } // in case: L <= g(x) <= R template pair solve(const FUNC &lag, VAL L, VAL R) { assert(L <= R); auto [f0, g0] = lag(VAL(0)); if (L <= g0 && g0 <= R) return {f0, VAL(0)}; if (g0 > R) return solve(lag, R); else return solve(lag, L); } template pair minimize(const FUNC &lag, VAL L, VAL R) { return solve(lag, L, R); } template pair maximize(const FUNC &lag, VAL L, VAL R) { auto reverse_lag = [&](VAL lambda) -> pair { auto [f, g] = lag(-lambda); return {-f, g}; }; auto [f, g] = solve(reverse_lag, L, R); return {-f, -g}; } }; // Alien DP // find the d-edges shortest path from vertex 0 on DAG by Lagrange relaxation // vertex: 0, 1, 2, ..., N, f(i, j) must be Monge template struct AlienDP { // inner values MongeShortestPath msp; AliensTrick at; // solver (random access ver.) template pair solve(int N, const FUNC &f, int D , const string &solver = "simple_larsch") { auto lag = [&](VAL lambda) -> pair { auto fg = [&](int i, int j) -> VAL { return f(i, j) + lambda; }; const auto &obj = msp.solve(N, fg, solver); auto cnt = msp.cnt[N]; auto res = obj.back().first - lambda * cnt; return {res, cnt}; }; return at.solve(lag, D); } // solver (slide access ver.) template pair solve (int N, const STATE &ini, const ADD &add, const DEL &del, const GETCOST &get, int D , const string &solver = "simple_larsch") { auto lag = [&](VAL lambda) -> pair { auto get_lag = [&](STATE &st) -> VAL { return get(st) + lambda; }; const auto &obj = msp.solve(N, ini, add, del, get_lag, solver); auto cnt = msp.cnt[N]; auto res = obj.back().first - lambda * cnt; return {res, cnt}; }; return at.solve(lag, D); } // debugger template void debug(int N, const FUNC &f, VAL start = 0, VAL goal = 10) { auto lag = [&](VAL lambda) -> void { auto fg = [&](int i, int j) -> VAL { return f(i, j) + lambda; }; const auto &dp = msp.solve(N, fg); auto cnt = msp.cnt[N]; auto res = dp.back().first - lambda * cnt; cout << lambda << ": " << res << "(" << cnt << "); ("; for (int i = 0; i < (int)dp.size(); i++) { if (i) cout << " "; cout << "<" << dp[i].first << ", " << dp[i].second << ">"; } cout << ")" << endl; }; for (VAL lambda = start; lambda <= goal; lambda++) lag(lambda); } }; // f: Monge, interval monotone ((N+1) x (N+1)) // dp[i][j] = min_{i <= k < j} (dp[i][k] + dp[k][j]) + f(i, j), in O(N^2) template VAL KnuthYao(int N, const FUNC &f) { VAL INF = numeric_limits::max() / 2; vector> dp(N+1, vector(N+1, INF)); vector> K(N+1, vector(N+1, -1)); for (int i = 0; i <= N; i++) { dp[i][i] = 0, K[i][i] = i; if (i < N) dp[i][i+1] = f(i, i+1), K[i][i+1] = i; } for (int between = 2; between <= N; between++) { for (int i = 0; i + between <= N; i++) { int j = i + between; for (int k = K[i][j-1]; k <= K[i+1][j]; k++) { VAL tmp = dp[i][k] + dp[k][j] + f(i, j); if (dp[i][j] > tmp) { dp[i][j] = tmp; K[i][j] = k; } } } } return dp[0][N]; } //------------------------------// // Examples //------------------------------// // COLOCON 2018 Final C - スペースエクスプローラー高橋君 void COLOCON_2018_final_C() { long long N; cin >> N; vector a(N), res(N); for (int i = 0; i < N; ++i) cin >> a[i]; MongeCHT cht(0, 210000, 1LL<<60); for (long long i = 0; i < N; ++i) { auto func = [i, &a](long long x) -> long long { return (x - i) * (x - i) + a[i]; }; cht.insert(func); } for (long long i = 0; i < N; ++i) res[i] = cht.query(i).first; for (int i = 0; i < N; ++i) cout << res[i] << endl; } // AtCoder EDPC Z - Frog 3 /* H は単調増加数列 chmin(dp[j], dp[i] + (H[j] - H[i])^2 + C) i -> j のコスト:(H[j] - H[i])^2 ...... 差の凸関数は Monge スタート: 0, ゴール: N-1 */ void EDPC_Z(const string solver = "simple_larsch") { long long N, C; cin >> N >> C; vector H(N); for (long long i = 0; i < N; i++) cin >> H[i]; auto func = [&](int i, int j) -> long long { return (H[j] - H[i]) * (H[j] - H[i]) + C; }; MongeShortestPath msp; const auto &res = msp.solve(N-1, func, solver); cout << res[N-1].first << endl; } // Codeforces Round 189 (Div. 1) C. Kalila and Dimna in the Logging Industry /* A: 単調増加, B: 単調減少, ともに長さ N i -> j のコストが、B[i] × A[j] で与えられる ..... 単調増加 × 単調減少は Monge スタート: 0, ゴール: N-1 */ void Codeforces_189_C(const string solver = "simple_larsch") { long long N; cin >> N; vector A(N), B(N); for (int i = 0; i < N; i++) cin >> A[i]; for (int i = 0; i < N; i++) cin >> B[i]; auto func = [&](int i, int j) -> long long { return B[i] * A[j]; }; MongeShortestPath msp; auto res = msp.solve(N-1, func, solver); cout << res[N-1].first << endl; } // yukicoder No.705 ゴミ拾い Hard /* A, X, Y: N 個 これらを区間に分割していく  dp[j] = min_{0 ≦ i < j}(dp[i] + |A[j-1] - X[i]|^3 + |-Y[i]|^3) i -> j のコスト:|A[j-1] - X[i]|^3 + |-Y[i]|^3 ...... 差の凸関数 (Monge) + 縞々 (Monge) -> Monge スタート: 0, ゴール: N */ void yukicoder_705(const string solver = "simple_larsch") { int N; cin >> N; vector A(N), X(N), Y(N); for (int i = 0; i < N; i++) cin >> A[i]; for (int i = 0; i < N; i++) cin >> X[i]; for (int i = 0; i < N; i++) cin >> Y[i]; auto func = [&](int i, int j) -> long long { long long dx = abs(A[j-1] - X[i]), dy = abs(Y[i]); return dx * dx * dx + dy * dy * dy; }; MongeShortestPath msp; auto res = msp.solve(N, func, solver); cout << res[N].first << endl; } // ABC 218 H - Red and Blue Lamps void ABC_218_H() { long long N, R; cin >> N >> R; vector A(N - 1); for (int i = 0; i < N - 1; i++) cin >> A[i]; auto cost = [&](int i, int j) -> long long { if (j - i <= 1) return 0; if (i == 0) return -A[j - 2]; else return -A[i - 1] - A[j - 2]; }; AlienDP ad; //ad.debug(N, cost); auto [resR, cntR] = ad.solve(N, cost, R); // both "larsch" and "simple_larsch" are OK auto [resB, cntB] = ad.solve(N, cost, N - R); auto res = max(-resR, -resB); cout << res << endl; } // yukicoder No.952 危険な火薬庫 /* 末尾にドアを追加する。 ノード 0, 1, ..., N, N+1 f(i, j) = (S[j-1] - S[i])^2 選ぶドアが k 個 → 区間の個数は、N+1-k */ void yukicoder_952() { int N; cin >> N; vector A(N + 1, 0), S(N + 2, 0); for (int i = 0; i < N; i++) cin >> A[i], S[i + 1] = S[i] + A[i]; auto f = [&](int i, int j) -> long long { return (S[j - 1] - S[i]) * (S[j - 1] - S[i]); }; MongeShortestPathWithDEdges msp; auto res = msp.solve(N + 1, f, N + 1); for (int k = 1; k <= N; k++) cout << res[N + 1 - k] << endl; } // Codeforces Round 438 (Div. 1 + Div. 2 combined) F. Yet Another Minimization Problem // by Monge 単一始点 d-辺最短路の d = 1, 2, ..., D における列挙 (by SMAWK 法, in O(ND)) void Codeforces438_F_enum() { long long N, K; cin >> N >> K; vector A(N); for (int i = 0; i < N; i++) cin >> A[i]; vector nums(N + 1, 0); long long left = 0, right = 0, score = 0; auto add = [&](int i) -> void { score += nums[A[i]]; nums[A[i]]++; }; auto del = [&](int i) -> void { nums[A[i]]--; score -= nums[A[i]]; }; auto f = [&](int i, int j) -> long long { while (left < i) del(left++); while (i < left) add(--left); while (right < j) add(right++); while (j < right) del(--right); return score; }; MongeShortestPathWithDEdges msp; auto res = msp.solve(N, f, K, "monotone"); // we should use slide access cout << res[K] << endl; } // Codeforces Round 438 (Div. 1 + Div. 2 combined) F. Yet Another Minimization Problem // by Alien DP (not the assumed solution) void Codeforces438_F_alien() { long long N, K; cin >> N >> K; vector A(N); for (int i = 0; i < N; i++) cin >> A[i]; struct STATE { vector nums; long long cost; STATE(int N) : nums(N + 1, 0), cost(0) {} }; STATE ini(N); auto add = [&](STATE &st, int i) -> void { st.cost += st.nums[A[i]]; st.nums[A[i]]++; }; auto del = [&](STATE &st, int i) -> void { st.nums[A[i]]--; st.cost -= st.nums[A[i]]; }; auto get = [&](STATE &st) -> long long { return st.cost; }; AlienDP adp; auto res = adp.solve(N, ini, add, del, get, K); // we should use slide access cout << res.first << endl; } // ABC 480 G - Zonal Score Minimization template struct SparseTable { using Func = function; // core member Func OP = [](const MeetSemiLattice &l, const MeetSemiLattice &r) { return min(l, r); }; vector> dat; vector height; SparseTable() {} SparseTable(const vector &vec) { init(vec); } SparseTable(const vector &vec, const Func &op) { init(vec, op); } void init(const vector &vec) { int n = (int)vec.size(), h = 1; while ((1<(1<>1]+1; for (int i = 0; i < n; ++i) dat[0][i] = vec[i]; for (int i = 1; i < h; ++i) { for (int j = 0; j < n; ++j) dat[i][j] = OP(dat[i-1][j], dat[i-1][min(j+(1<<(i-1)),n-1)]); } } void init(const vector &vec, const Func &op) { OP = op; init(vec); } MeetSemiLattice get(int a, int b) { return OP(dat[height[b-a]][a], dat[height[b-a]][b-(1<> N; vector A(N); for (int i = 0; i < N; ++i) cin >> A[i]; SparseTable stmi(A); SparseTable stma(A, [&](long long p, long long q){return max(p, q);}); auto func = [&](int l, int r) -> long long { assert(r - l >= 2); return stma.get(l, r) - stmi.get(l, r); }; auto res = antiMongeDDSMAWK(N, func, 2); cout << res.back().first << endl; } int main() { ll N, A, B, W; cin >> N >> A >> B >> W; vll D(N); cin >> D; auto func = [&](ll i, ll j) -> ll { ll len = j - i; return D[j-1] - A * (len - 1) + B * len * (len - 1) / 2; }; MongeShortestPath opt; auto x = opt.solve(N, func); ll res = x.back().first + W; REP(i, N+1) { ll w = x[i].first - A * (N - i) + B * (N - i) * (N - i + 1) / 2 + W; //cout << i << ": " << w << endl; chmin(res, w); } cout << res << endl; //COUT(x); }