제출 #1279899

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1279899		goldenbull	Mobile (BOI12_mobile)	C++17	13 / 100	1098 ms	40376 KiB

mobile

#include <bits/stdc++.h>
#define TIME (1.0 * clock() / CLOCKS_PER_SEC)
#define FOR(i,a,b) for (int i=(a),_b=(b); i<=_b; i++)
#define FOD(i,a,b) for (int i=(a),_b=(b); i>=_b; i--)
#define FUL(n) (((1LL)<<(n))-1)
#define BIT(n,k) (((n)>>(k))&1)
#define fi first
#define se second
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define sz(x) ((int)(x).size())
#define sqr(x) (1LL * (x) * (x))
using namespace std;
using ll = long long;
using ull = uint64_t;
using ld = double;
template<class T> using ve = vector<T>;
using vi = vector<int>;
using vll = vector<ll>;
using ii = pair<int,int>;
using pll = pair<ll,ll>;
using pld = pair<ld,ld>;

const char el = '\n';
template<class T> void print(T a[], int n) { FOR(i,0,n-1) cerr << a[i] << ' '; cerr << el; }
template<class T, class U> bool maxi(T& x, const U& y) { return y>x?(x=y,1):0; }
template<class T, class U> bool mini(T& x, const U& y) { return y<x?(x=y,1):0; }

const int maxn = 1e6+7;
const ld eps = 1e-3;

int n;
int L;
ii p[maxn];

pld coverage(int x, int y, ld r) {
	if (r < abs(y)) exit(1);
	ld s = sqrt(abs(r*r - 1.0*y*y));
	return {1.0*x - s, 1.0*x + s};
}

bool ok(ld k) {
	ve<pld> lr;
	FOR(i,1,n) if (abs(p[i].se) <= k) {
		lr.pb(coverage(p[i].fi, p[i].se, k));
	}
	if (!sz(lr)) return false;
	sort(all(lr));
	ld cl = lr[0].fi, cr = lr[0].se;
	FOR(i,1,sz(lr)-1) {
		if (lr[i].fi > cr) return false;
		maxi(cr, lr[i].se);
	}
	return (cl <= 0) && (cr >= L);
}

void solve() {
	cin>>n>>L;
	FOR(i,1,n) cin>>p[i].fi>>p[i].se;

	ld l = 0, r = 3.0*L;
	int cnt = 0;
	while (abs(l-r) >= eps) {
		ld mid = (l+r)/2;
		if (ok(mid)) r = mid;
		else l = mid;

		cnt++;
	}
	cout << fixed << setprecision(6);
	cout << l;

//	cerr << el;
//	cerr << cnt;
}

#define IN ".inp"
#define OUT ".out"
//#define NAME "test"
signed main() {
	ios_base::sync_with_stdio(false); cin.tie(nullptr);
	#ifndef NAME
		if (fopen("test.inp", "r")) freopen("test.inp", "r", stdin);
	#endif
	#ifdef NAME
		freopen(NAME IN, "r", stdin);
		freopen(NAME OUT, "w", stdout);
	#endif

	int tt=1;
//	cin>>tt;
	while (tt--) solve();

	cerr << el << "Time elapsed: " << TIME << " s";
	return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

mobile.cpp: In function 'int main()':
mobile.cpp:83:52: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   83 |                 if (fopen("test.inp", "r")) freopen("test.inp", "r", stdin);
      |                                             ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 0 / 4
• Subtask 3: 0 / 4
• Subtask 4: 4 / 4
• Subtask 5: 0 / 4
• Subtask 6: 5 / 5
• Subtask 7: 0 / 5
• Subtask 8: 0 / 5
• Subtask 9: 0 / 5
• Subtask 10: 0 / 5
• Subtask 11: 0 / 5
• Subtask 12: 0 / 5
• Subtask 13: 0 / 5
• Subtask 14: 0 / 5
• Subtask 15: 0 / 5
• Subtask 16: 0 / 5
• Subtask 17: 0 / 5
• Subtask 18: 0 / 5
• Subtask 19: 0 / 5
• Subtask 20: 0 / 5
• Subtask 21: 0 / 5