Submission #1033372

#	Time	Username	Problem	Language	Result	Execution time	Memory
1033372		vjudge1	Mobile (BOI12_mobile)	C++17	50 / 100	64 ms	3932 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 minimize(T1 &a, T2 b) {
	if (a > b) a = b; else return 0; return 1;
}
template<typename T1, typename T2> bool maximize(T1 &a, T2 b) {
	if (a < b) a = b; else return 0; return 1;
}

const int MAX = 100100;
int n, L;
int x[MAX];
int y[MAX];

bool ok(double r) {
    double c = 0;
    for (int i = 1; i <= n; ++i) {
        double delta = sqrt(r * r - 1LL * y[i] * y[i]);
        if (x[i] - delta <= c) {
            maximize(c, x[i] + delta);
        }
    }
    return c < L;
}

void process(void) {
    cin >> n >> L;
    for (int i = 1; i <= n; ++i) {
        cin >> x[i] >> y[i];
    }
    double l = 0, r = 1.5e9;
    for (int t = 0; t < 100; ++t) {
        double mid = (l + r) / 2;
        if (ok(mid)) l = mid;
        else r = mid;
    }
    cout << setprecision(12) << 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:53:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   53 |   freopen(task".inp", "r",  stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
mobile.cpp:54:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   54 |   freopen(task".out", "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 4 / 4
• Subtask 3: 4 / 4
• Subtask 4: 4 / 4
• Subtask 5: 4 / 4
• Subtask 6: 5 / 5
• Subtask 7: 5 / 5
• Subtask 8: 5 / 5
• Subtask 9: 5 / 5
• Subtask 10: 5 / 5
• Subtask 11: 5 / 5
• Subtask 12: 0 / 5
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• Subtask 21: 0 / 5