// // Totally Monotone 単一始点最短路問題 by D&D SMAWK // 頂点数 N+1 の DAG, 頂点 i, j 間のコスト f(i, j) が Totally Monotone であることを仮定 (列方向に >< がない) // O(N log N) // // verified // AtCoder EDPC Z - Frog 3 // https://atcoder.jp/contests/dp/tasks/dp_z // // Codeforces Round 189 (Div. 1) C. Kalila and Dimna in the Logging Industry // https://codeforces.com/contest/319/problem/C // // yukicoder No.705 ゴミ拾い Hard // https://yukicoder.me/problems/no/705 // // Reference: // tatyam: Monge の手引き書 // https://speakerdeck.com/tatyam_prime/monge-noshou-yin-shu // #include using namespace std; // find min_j f(i, j) for all i, by Monotone Minima, O(H + W log H) // f(i, j) must be totally monotone 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; } //------------------------------// // Examples //------------------------------// // 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() { 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; }; auto res = DDSMAWK(N-1, func); 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() { 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]; }; auto res = DDSMAWK(N-1, func); 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() { 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; }; auto res = DDSMAWK(N, func); cout << res[N].first << endl; } int main() { //EDPC_Z(); //Codeforces_189_C(); yukicoder_705(); }