#include <bits/stdc++.h> #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> #define ll long long #define db double #define pii pair<int, int> #define pll pair<ll, ll> #define fi first #define se second #define pb push_back #define all(x) begin(x), end(x) #define allr(x) rbegin(x), rend(x) #define szx(x) ((int)(x).size()) #define FOR(i, a, b) for (int i = a, _b = (b); i <= _b; ++i) #define ROF(i, a, b) for (int i = a, _b = (b); i >= _b; --i) #define REP(i, n) for (int i = 0, _n = (n); i < _n; ++i) #define endl '\n' #define inf 1000000007 #define mod 1000000007 // #define mod 998244353 using namespace std; using namespace __gnu_pbds; void setIO() { ios::sync_with_stdio(0); cin.tie(0); } void openFile(string filename = "") { if (!filename.empty()) if (ifstream(filename + ".in")) { freopen((filename + ".in").c_str(), "r", stdin); freopen((filename + ".out").c_str(), "w", stdout); } } ll binpow(ll a, ll b, int m = mod) { ll res = 1; a %= m; while (b) { if (b & 1) res = (a * res) % m; a = (a * a) % m; b >>= 1; } return res; } const int FMAX = 2e5 + 5; ll fact[FMAX], invf[FMAX]; void process() { fact[1] = fact[0] = invf[1] = invf[0] = 1; FOR(i, 2, FMAX - 1) fact[i] = (fact[i - 1] * i) % mod; invf[FMAX - 1] = binpow(fact[FMAX - 1], mod - 2, mod); ROF(i, FMAX - 1, 1) invf[i - 1] = invf[i] * i % mod; } ll comb(int a, int b) { b = min(b, a - b); if (a < 0 || b < 0) return 0; return fact[a] * (invf[b] * invf[a - b] % mod) % mod; } const int PMAX = 1e6 + 5; bool prime[PMAX + 1]; void sieve() { fill(prime, prime + PMAX + 1, 1); prime[0] = prime[1] = 0; for (int i = 2; i * i <= PMAX; i++) { if (prime[i] == 0) continue; prime[i] = 1; for (ll j = i * i; j <= PMAX; j += i) prime[j] = 0; } } struct DSU { vector<int> comp; ll ans = 0; DSU(int n) { comp.assign(n + 5, -1); } int find(int v) { return comp[v] < 0 ? v : comp[v] = find(comp[v]); } void unite(int u, int v) { u = find(u), v = find(v); if (u == v) return; if (comp[u] > comp[v]) swap(u, v); comp[u] += comp[v]; comp[v] = u; } int getsz(int v) { return -comp[find(v)]; } bool same(int u, int v) { return find(u) == find(v); } }; struct Point { db x, y; Point(db x, db y) : x(x), y(y) {} Point() {}; }; struct Vector { int x, y; Vector(Point A, Point B) { x = A.x - B.x; y = A.y - B.y; } Vector(int x, int y) : x(x), y(y) {}; Vector PerpenVec() { return Vector(y, -x); } }; struct Line { int a, b; db c; Line(Vector v, Point A) { Vector PerpenVec = v.PerpenVec(); a = PerpenVec.x; b = PerpenVec.y; c = -(a * A.x + b * A.y); } }; Line bisectorLine(Point A, Point B) { Point midPoint = Point((A.x + B.x) / 2, (A.y + B.y) / 2); Vector v = Vector(A, B).PerpenVec(); return Line(v, midPoint); } Point intersec(Line A, Line B) { int delta = A.b * B.a - A.a * B.b; if (delta == 0) return Point(-inf, -inf); return Point(1.0 * (A.c * B.b - A.b * B.c) / delta, -1.0 * (A.c * B.a - A.a * B.c) / delta); } db distance(Point A, Point B) { return sqrt((A.x - B.x) * (A.x - B.x) + (A.y - B.y) * (A.y - B.y)); } const int MAX = 1e6 + 5; int n, l; Point stations[MAX]; Line Ox = Line(Vector(1, 0), Point(0, 0)); void solve() { stack<Point> st; REP(i, n) { while (szx(st) >= 2) { Point B = st.top(); st.pop(); Point A = st.top(); Line b1 = bisectorLine(A, B), b2 = bisectorLine(B, stations[i]); if (intersec(b1, Ox).x < intersec(b2, Ox).x) { st.push(B); break; } } st.push(stations[i]); } db ans = inf; while (szx(st) >= 2) { Point A = st.top(); st.pop(); Point B = st.top(); Point C = intersec(bisectorLine(A, B), Ox); db d = distance(C, A); if (C.x >= 0 && C.x <= l) ans = min(ans, d); } cout << ans; } void input() { cin >> n >> l; REP(i, n) cin >> stations[i].x >> stations[i].y; } void preprocess() {} int main() { setIO(); openFile("main"); int t = 1; // cin >> t; preprocess(); while (t--) { input(); solve(); } }

mobile.cpp: In function 'void openFile(std::string)':
mobile.cpp:32:20: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |             freopen((filename + ".in").c_str(), "r", stdin);
      |             ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mobile.cpp:33:20: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |             freopen((filename + ".out").c_str(), "w", stdout);
      |             ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~