#include #include using namespace std; #define rep(i,n) for(long long i = 0; i < (long long)(n); i++) #define repi(i,a,b) for(long long i = (long long)(a); i < (long long)(b); i++) #define pb push_back #define all(x) (x).begin(), (x).end() #define fi first #define se second #define mt make_tuple #define mp make_pair template bool chmin(T1 &a, T2 b) { return b < a && (a = b, true); } template bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); } using ll = long long; using vll = vector; using vvll = vector; using P = pair; using ld = long double; using vld = vector; using vi = vector; using vvi = vector; vll conv(vi& v) { vll r(v.size()); rep(i, v.size()) r[i] = v[i]; return r; } inline void input(int &v){ v=0;char c=0;int p=1; while(c<'0' || c>'9'){if(c=='-')p=-1;c=getchar();} while(c>='0' && c<='9'){v=(v<<3)+(v<<1)+c-'0';c=getchar();} v*=p; } template ostream &operator<<(ostream &o, const pair &v) { o << "(" << v.first << ", " << v.second << ")"; return o; } template struct seq{}; template struct gen_seq : gen_seq{}; template struct gen_seq<0, Is...> : seq{}; template void print_tuple(basic_ostream& os, Tuple const& t, seq){ using s = int[]; (void)s{0, (void(os << (Is == 0? "" : ", ") << get(t)), 0)...}; } template auto operator<<(basic_ostream& os, tuple const& t) -> basic_ostream& { os << "("; print_tuple(os, t, gen_seq()); return os << ")"; } ostream &operator<<(ostream &o, const vvll &v) { rep(i, v.size()) { rep(j, v[i].size()) o << v[i][j] << " "; o << endl; } return o; } template ostream &operator<<(ostream &o, const vector &v) { o << '['; rep(i, v.size()) o << v[i] << (i != v.size()-1 ? ", " : ""); o << "]"; return o; } template ostream &operator<<(ostream &o, const deque &v) { o << '['; rep(i, v.size()) o << v[i] << (i != v.size()-1 ? ", " : ""); o << "]"; return o; } template ostream &operator<<(ostream &o, const set &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it << (next(it) != m.end() ? ", " : ""); o << "]"; return o; } template ostream &operator<<(ostream &o, const unordered_set &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it << (next(it) != m.end() ? ", " : ""); o << "]"; return o; } template ostream &operator<<(ostream &o, const map &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it << (next(it) != m.end() ? ", " : ""); o << "]"; return o; } template ostream &operator<<(ostream &o, const unordered_map &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it; o << "]"; return o; } vector range(const int x, const int y) { vector v(y - x + 1); iota(v.begin(), v.end(), x); return v; } template istream& operator>>(istream& i, vector& o) { rep(j, o.size()) i >> o[j]; return i;} template ostream &operator<<(ostream &o, const priority_queue &v) { auto tmp = v; while (tmp.size()) { auto x = tmp.top(); tmp.pop(); o << x << " ";} return o; } template ostream &operator<<(ostream &o, const queue &v) { auto tmp = v; while (tmp.size()) { auto x = tmp.front(); tmp.pop(); o << x << " ";} return o; } template ostream &operator<<(ostream &o, const stack &v) { auto tmp = v; while (tmp.size()) { auto x = tmp.top(); tmp.pop(); o << x << " ";} return o; } template unordered_map counter(vector vec){unordered_map ret; for (auto&& x : vec) ret[x]++; return ret;}; string substr(string s, P x) {return s.substr(x.fi, x.se - x.fi); } void vizGraph(vvll& g, int mode = 0, string filename = "out.png") { ofstream ofs("./out.dot"); ofs << "digraph graph_name {" << endl; set

memo; rep(i, g.size()) rep(j, g[i].size()) { if (mode && (memo.count(P(i, g[i][j])) || memo.count(P(g[i][j], i)))) continue; memo.insert(P(i, g[i][j])); ofs << " " << i << " -> " << g[i][j] << (mode ? " [arrowhead = none]" : "")<< endl; } ofs << "}" << endl; ofs.close(); system(((string)"dot -T png out.dot >" + filename).c_str()); } size_t random_seed; namespace std { using argument_type = P; template<> struct hash { size_t operator()(argument_type const& x) const { size_t seed = random_seed; seed ^= hash{}(x.fi); seed ^= (hash{}(x.se) << 1); return seed; } }; }; // hash for various class struct timeval start; double sec() { struct timeval tv; gettimeofday(&tv, NULL); return (tv.tv_sec - start.tv_sec) + (tv.tv_usec - start.tv_usec) * 1e-6; } struct init_{init_(){ ios::sync_with_stdio(false); cin.tie(0); gettimeofday(&start, NULL); struct timeval myTime; struct tm *time_st; gettimeofday(&myTime, NULL); time_st = localtime(&myTime.tv_sec); srand(myTime.tv_usec); random_seed = RAND_MAX / 2 + rand() / 2; }} init__; #define ldout fixed << setprecision(40) #define EPS (double)1e-14 #define INF (ll)1e18 #define mo (ll)(1e9+7) double dx(double a, double b, double r, double x) { double dx_result; dx_result = 2*(-a + x)*(-a - r + sqrt(pow(r, 2) + pow(a - x, 2)))/sqrt(pow(r, 2) + pow(a - x, 2)) + 2*(-b + x)*(-b + r + sqrt(pow(r, 2) + pow(b - x, 2)))/sqrt(pow(r, 2) + pow(b - x, 2)); return dx_result; } double dr(double a, double b, double r, double x) { double dr_result; dr_result = (2*r/sqrt(pow(r, 2) + pow(a - x, 2)) - 2)*(-a - r + sqrt(pow(r, 2) + pow(a - x, 2))) + (2*r/sqrt(pow(r, 2) + pow(b - x, 2)) + 2)*(-b + r + sqrt(pow(r, 2) + pow(b - x, 2))); return dr_result; } double fx(double a, double r, double x) { double fx_result; fx_result = -a - r + sqrt(pow(r, 2) + pow(a - x, 2)); return fx_result; } double fy(double b, double r, double x) { double fy_result; fy_result = -b + r + sqrt(pow(r, 2) + pow(b - x, 2)); return fy_result; } double d2x(double a, double b, double r_0, double r_1, double x_0, double x_1, double y_0, double y_1) { double d2x_result; d2x_result = 2*(-a + x_1)*(-a - r_1 + sqrt(pow(y_1, 2) + pow(a - x_1, 2)))/sqrt(pow(y_1, 2) + pow(a - x_1, 2)) + 2*(-b + x_1)*(-b + r_1 + sqrt(pow(y_1, 2) + pow(b - x_1, 2)))/sqrt(pow(y_1, 2) + pow(b - x_1, 2)) + 2*(-x_0 + x_1)*(-r_0 - r_1 + sqrt(pow(x_0 - x_1, 2) + pow(y_0 - y_1, 2)))/sqrt(pow(x_0 - x_1, 2) + pow(y_0 - y_1, 2)); return d2x_result; } double d2y(double a, double b, double r_0, double r_1, double x_0, double x_1, double y_0, double y_1) { double d2y_result; d2y_result = 2*y_1*(-b + r_1 + sqrt(pow(y_1, 2) + pow(b - x_1, 2)))/sqrt(pow(y_1, 2) + pow(b - x_1, 2)) + 2*y_1*(-a - r_1 + sqrt(pow(y_1, 2) + pow(a - x_1, 2)))/sqrt(pow(y_1, 2) + pow(a - x_1, 2)) + 2*(-y_0 + y_1)*(-r_0 - r_1 + sqrt(pow(x_0 - x_1, 2) + pow(y_0 - y_1, 2)))/sqrt(pow(x_0 - x_1, 2) + pow(y_0 - y_1, 2)); return d2y_result; } double d2r(double a, double b, double r_0, double r_1, double x_0, double x_1, double y_0, double y_1) { double d2r_result; d2r_result = 2*a - 2*b + 2*r_0 + 6*r_1 - 2*sqrt(pow(y_1, 2) + pow(a - x_1, 2)) + 2*sqrt(pow(y_1, 2) + pow(b - x_1, 2)) - 2*sqrt(pow(x_0 - x_1, 2) + pow(y_0 - y_1, 2)); return d2r_result; } double fa(double a, double r_1, double x_1, double y_1) { double fa_result; fa_result = -a - r_1 + sqrt(pow(y_1, 2) + pow(a - x_1, 2)); return fa_result; } double fb(double b, double r_1, double x_1, double y_1) { double fb_result; fb_result = -b + r_1 + sqrt(pow(y_1, 2) + pow(b - x_1, 2)); return fb_result; } double fc(double r_0, double r_1, double x_0, double x_1, double y_0, double y_1) { double fc_result; fc_result = -r_0 - r_1 + sqrt(pow(x_0 - x_1, 2) + pow(y_0 - y_1, 2)); return fc_result; } int main(void) { ll n; cin >> n; double a, b; cin >> a >> b; assert(1<=n&&n<=1000); assert(1<=a&&a 100) continue; // cout << xx << " " << yy << " " << score << endl;; } double x = b+1, y = -1, r = b/2+1; if (n % 2 == 0) { double dt = 0.01; rep(_, 10000) { // cout << x << " " << r << endl; double delta_x = dx(a, b, r, x); double delta_r = dr(a, b, r, x); // cout << delta_x << " " << delta_r << "delta"<