#line 1 "template/template.hpp" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define rep(i, a, n) for (int i = (int)(a); i < (int)(n); i++) #define rrep(i, a, n) for (int i = ((int)(n)-1); i >= (int)(a); i--) #define Rep(i, a, n) for (i64 i = (i64)(a); i < (i64)(n); i++) #define RRep(i, a, n) for (i64 i = ((i64)(n)-i64(1)); i >= (i64)(a); i--) #define all(v) (v).begin(), (v).end() #define rall(v) (v).rbegin(), (v).rend() #line 2 "template/debug_template.hpp" #line 4 "template/debug_template.hpp" namespace ebi { #ifdef LOCAL #define debug(...) \ std::cerr << "LINE: " << __LINE__ << " [" << #__VA_ARGS__ << "]:", \ debug_out(__VA_ARGS__) #else #define debug(...) #endif void debug_out() { std::cerr << std::endl; } template void debug_out(Head h, Tail... t) { std::cerr << " " << h; if (sizeof...(t) > 0) std::cerr << " :"; debug_out(t...); } } #line 2 "template/int_alias.hpp" #line 4 "template/int_alias.hpp" namespace ebi { using std::size_t; using i8 = std::int8_t; using u8 = std::uint8_t; using i16 = std::int16_t; using u16 = std::uint16_t; using i32 = std::int32_t; using u32 = std::uint32_t; using i64 = std::int64_t; using u64 = std::uint64_t; using i128 = __int128_t; using u128 = __uint128_t; } #line 2 "template/io.hpp" #line 6 "template/io.hpp" namespace ebi { template std::ostream &operator<<(std::ostream &os, const std::pair &pa) { return os << pa.first << " " << pa.second; } template std::istream &operator>>(std::istream &os, std::pair &pa) { return os >> pa.first >> pa.second; } template std::ostream &operator<<(std::ostream &os, const std::vector &vec) { for (std::size_t i = 0; i < vec.size(); i++) os << vec[i] << (i + 1 == vec.size() ? "" : " "); return os; } template std::istream &operator>>(std::istream &os, std::vector &vec) { for (T &e : vec) std::cin >> e; return os; } template std::ostream &operator<<(std::ostream &os, const std::optional &opt) { if (opt) { os << opt.value(); } else { os << "invalid value"; } return os; } void fast_io() { std::cout << std::fixed << std::setprecision(15); std::cin.tie(nullptr); std::ios::sync_with_stdio(false); } } // namespace ebi #line 2 "template/utility.hpp" #line 5 "template/utility.hpp" #line 7 "template/utility.hpp" namespace ebi { template inline bool chmin(T &a, T b) { if (a > b) { a = b; return true; } return false; } template inline bool chmax(T &a, T b) { if (a < b) { a = b; return true; } return false; } constexpr i64 LNF = std::numeric_limits::max() / 4; constexpr int INF = std::numeric_limits::max() / 2; const std::vector dy = {1, 0, -1, 0, 1, 1, -1, -1}; const std::vector dx = {0, 1, 0, -1, 1, -1, 1, -1}; } // namespace ebi #line 2 "graph/template.hpp" #line 4 "graph/template.hpp" namespace ebi { template struct Edge { int to; T cost; Edge(int _to, T _cost = 1) : to(_to), cost(_cost) {} }; template struct Graph : std::vector>> { using std::vector>>::vector; void add_edge(int u, int v, T w, bool directed = false) { (*this)[u].emplace_back(v, w); if (directed) return; (*this)[v].emplace_back(u, w); } }; struct graph : std::vector> { using std::vector>::vector; void add_edge(int u, int v, bool directed = false) { (*this)[u].emplace_back(v); if (directed) return; (*this)[v].emplace_back(u); } }; } // namespace ebi #line 3 "a.cpp" namespace ebi { template void arg_sort_ll(std::vector> &a) { using Point = std::pair; int n = a.size(); std::vector ps(4, std::vector()); auto idx = [](Point v) -> int { if (v.second >= 0) return (v.first >= 0) ? 0 : 1; else return (v.first >= 0) ? 3 : 2; }; for (auto p : a) { assert(!(p.first == 0 && p.second == 0)); ps[idx(p)].emplace_back(p); } a.clear(); a.reserve(n); for (int j = 0; j < 4; j++) { int i = (3 + j) % 4; std::sort(ps[i].begin(), ps[i].end(), [](Point &p1, Point &p2) -> bool { T flag = p1.first * p2.second - p2.first * p1.second; return flag == 0 ? (p1.first * p1.first + p1.second * p1.second < p2.first * p2.first + p2.second * p2.second) : flag > 0; }); for (auto &p : ps[i]) a.emplace_back(p); } return; } struct random_number_generator { std::random_device rnd; std::mt19937_64 mt; int get(int a, int b) { std::uniform_int_distribution dist(a, b-1); return dist(mt); } }; void main_() { int n; i64 w, h; std::cin >> n >> w >> h; std::vector> ps(n); std::vector xs; for(auto &[x, y]: ps) { std::cin >> x >> y; xs.emplace_back(x); } std::sort(all(xs)); xs.erase(std::unique(all(xs)), xs.end()); std::vector arg_ord; { std::vector> ret; std::map, int> map; rep(i,0,n) { auto [x, y] = ps[i]; ret.emplace_back(2 * x, 2 * y - h); map[{2 * x, 2 * y - h}] = i; } arg_sort_ll(ret); for(auto [x, y]: ret) { arg_ord.emplace_back(map[{x, y}]); } } using ld = long double; ld ans = std::numeric_limits::max(); auto calc_score = [](const std::vector &a) -> ld { if(a[2] == 0) return 0; return ld(a[0]) - ld(a[1] * a[1]) / ld(4 * a[2]); }; random_number_generator rnd; for(auto tx: xs) { std::vector u(3, 0), d(3, 0); for(auto [x, y]: ps) { if(x < tx) { u[0] += (y - h) * (y - h); u[1] += -2 * (y - h) * x; u[2] += x * x; } else { d[0] += y * y; d[1] += -2 * x * y; d[2] += x * x; } } if(rnd.get(0, 10)) chmin(ans, calc_score(u) + calc_score(d)); for(auto i: arg_ord) { auto [x, y] = ps[i]; if(x < tx) { u[0] -= (y - h) * (y - h); u[1] -= -2 * (y - h) * x; u[2] -= x * x; d[0] += y * y; d[1] += -2 * x * y; d[2] += x * x; } else { d[0] -= y * y; d[1] -= -2 * x * y; d[2] -= x * x; u[0] += (y - h) * (y - h); u[1] += -2 * (y - h) * x; u[2] += x * x; } if(rnd.get(0, 10)) chmin(ans, calc_score(u) + calc_score(d)); } } std::cout << ans << '\n'; } } // namespace ebi int main() { ebi::fast_io(); int t = 1; // std::cin >> t; while (t--) { ebi::main_(); } return 0; }