Submission #990995

#	Time	Username	Problem	Language	Result	Execution time	Memory
990995		chanhchuong123	Mobile (BOI12_mobile)	C++14	0 / 100	1020 ms	8276 KiB

mobile

#include<bits/stdc++.h>
using namespace std;

const bool multiTest = false;
#define task ""
#define fi first
#define se second
#define MASK(i) (1LL << (i))
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define BIT(mask, i) ((mask) >> (i) & 1)

template<typename T1, typename T2> bool mini(T1 &a, T2 b) {
	if (a > b) a = b; else return 0; return 1;
}
template<typename T1, typename T2> bool maxi(T1 &a, T2 b) {
	if (a < b) a = b; else return 0; return 1;
}

const int MAX = 1000100;
int n, l, m;
int x[MAX];
int y[MAX];

bool ok(double dist) {
    if (x[1] - sqrt(dist * dist - 1LL * y[1] * y[1]) >= 0) return true;
    if (x[m] + sqrt(dist * dist - 1LL * y[m] * y[m]) <= l) return true;
    for (int i = 1; i <= m - 1; ++i) {
        double l = x[i] + sqrt(dist * dist - 1LL * y[i] * y[i]), r = x[i + 1] - sqrt(dist * dist - 1LL * y[i + 1] * y[i + 1]);
        if (l <= r) return true;
    }
    return false;
}

void process(void) {
    cin >> n >> l;
    x[0] = -1e9 - 7;
    y[0] = -1e9 - 7;
    for (int i = 1; i <= n; ++i) {
        int X, Y;   cin >> X >> Y;
        if (x[m] != X) {
            ++m; x[m] = X;
            y[m] = abs(Y);
        } else mini(y[m], abs(Y));
    }
    double l = 0, r = 5 * 5e9 + 100;
    for (int t = 1; t <= 150; ++t) {
        double mid = (l + r) / 2;
        if (ok(mid)) l = mid;
        else r = mid;
    }
    cout << setprecision(6) << fixed << l;
}

int main(void) {
	ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
	if (fopen(task".inp", "r")) {
		freopen(task".inp", "r",  stdin);
		freopen(task".out", "w", stdout);
	}

	int nTest = 1; if (multiTest) cin >> nTest;
	while (nTest--) {
		process();
	}

	return 0;
}

Compilation message (stderr)

mobile.cpp: In function 'int main()':
mobile.cpp:58:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   58 |   freopen(task".inp", "r",  stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
mobile.cpp:59:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   59 |   freopen(task".out", "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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