Submission #1287606

#	Time	Username	Problem	Language	Result	Execution time	Memory
1287606		wedonttalkanymore	Mobile (BOI12_mobile)	C++20	8 / 100	41 ms	3524 KiB

mobile

#include <bits/stdc++.h>
/*
    Phia ben kia dai duong cung chi co
    Bo cat nang niu bien thoi
*/
using namespace std;
using ll = long long;

#define int long long
#define pii pair<ll, ll>
#define fi first
#define se second

const ll N = 2e5 + 5, inf = 1e18, mod = 1e9 + 7, block = 320, lim = 19;

int n, L;
pii a[N];

bool check(long double mid) {
    long double x = mid * mid;
    long double maxx = 1e-12;
    for (int i = 1; i <= n; i++) {
        if (x < a[i].se * a[i].se) continue;
        long double tmp = 1.0 * sqrtl(x - a[i].se * a[i].se);
        long double x1 = a[i].fi - tmp;
        long double x2 = a[i].fi + tmp;
        if (x1 <= maxx) maxx = max(maxx, x2);
    }
    return maxx >= L;
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    if (fopen(".inp", "r")) {
        freopen(".inp", "r", stdin);
        freopen(".out", "w", stdout);
    }
    cin >> n >> L;
    for (int i = 1; i <= n; i++) cin >> a[i].fi >> a[i].se;
    long double l = 0, r = 1.0 * 2e9, ans = 0;
    while((r - l) > 1e-3) {
        long double mid = (l + r) / 2;
        if (check(mid)) {
            ans = mid;
            r = mid;
        }
        else l = mid;
    }
    cout << ans;
    return 0;
}

Compilation message (stderr)

mobile.cpp: In function 'int main()':
mobile.cpp:36:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |         freopen(".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~
mobile.cpp:37:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen(".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~

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