#line 1 "other_algorithms/test/monge_shortest_path.yuki705.test.cpp" #define PROBLEM "https://yukicoder.me/problems/no/705" #line 2 "other_algorithms/monge_shortest_path.hpp" #include #include // Shortest path of Monge-weighted graph // Variant of LARSCH Algorithm: https://noshi91.hatenablog.com/entry/2023/02/18/005856 // Complexity: O(n log n) // // Given a directed graph with n vertices and weighted edges // (w(i, j) = cost_callback(i, j) (i < j)), // this class calculates the shortest path from vertex 0 to all other vertices. template struct monge_shortest_path { std::vector dist; // dist[i] = shortest distance from 0 to i std::vector amin; // amin[i] = previous vertex of i in the shortest path template void _check(int i, int k, F cost_callback) { if (i <= k) return; if (Cost c = dist[k] + cost_callback(k, i); c < dist[i]) dist[i] = c, amin[i] = k; } template void _rec_solve(int l, int r, F cost_callback) { if (r - l == 1) return; const int m = (l + r) / 2; for (int k = amin[l]; k <= amin[r]; ++k) _check(m, k, cost_callback); _rec_solve(l, m, cost_callback); for (int k = l + 1; k <= m; ++k) _check(r, k, cost_callback); _rec_solve(m, r, cost_callback); } template Cost solve(int n, F cost_callback) { assert(n > 0); dist.resize(n); amin.assign(n, 0); dist[0] = Cost(); for (int i = 1; i < n; ++i) dist[i] = cost_callback(0, i); _rec_solve(0, n - 1, cost_callback); return dist.back(); } template int num_edges() const { int ret = 0; for (int c = (int)amin.size() - 1; c >= 0; c = amin[c]) ++ret; return ret; } }; // Find shortest path length from 0 to n - 1 with k edges, min_edges <= k <= max_edges // https://noshi91.hatenablog.com/entry/2022/01/13/001217 template Cost monge_shortest_path_with_specified_edges(int n, int min_edges, int max_edges, Cost max_abs_cost, F cost_callback) { assert(1 <= n); assert(0 <= min_edges); assert(min_edges <= max_edges); assert(max_edges <= n - 1); monge_shortest_path msp; auto eval = [&](Cost p) -> Cost { msp.solve(n, [&](int i, int j) { return cost_callback(i, j) - p; }); return -msp.dist.back() - p * (p < 0 ? max_edges : min_edges); }; Cost lo = -max_abs_cost * 3, hi = max_abs_cost * 3; while (lo + 1 < hi) { Cost p = (lo + hi) / 2, f = eval(p), df = eval(p + 1) - f; if (df == Cost()) { return -f; } else { (df < Cost() ? lo : hi) = p; } } Cost flo = eval(lo), fhi = eval(hi); return flo < fhi ? -flo : -fhi; } #line 3 "other_algorithms/test/monge_shortest_path.yuki705.test.cpp" #line 5 "other_algorithms/test/monge_shortest_path.yuki705.test.cpp" #include #include using namespace std; int main() { cin.tie(nullptr), ios::sync_with_stdio(false); int N; cin >> N; vector A(N), X(N), Y(N); for (auto &a : A) cin >> a; for (auto &x : X) cin >> x; for (auto &y : Y) cin >> y; auto weight = [&](int j, int i) { assert(j < i); --i; const long long dx = abs(A.at(i) - X.at(j)), dy = Y.at(j); return dx * dx * dx + dy * dy * dy; }; monge_shortest_path msp; cout << msp.solve(N + 1, weight) << '\n'; }