oj.uz

Submission #1056852

# Submission time Handle Problem Language Result Execution time Memory
1056852 2024-08-13T11:47:50 Z TimAni Mobile (BOI12_mobile) C++17
0 / 100
 1000 ms 31572 KB 
// time-limit: 3000

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

const double eps = 1e-3;

struct point {
    double x{}, y{};
};

void solve() {
    int n;
    double L; 
    cin >> n >> L;
    vector<point> p(n);
    for(int i = 0; i < n; i++) {
        cin >> p[i].x >> p[i].y;
    }
    auto intersection = [&](const point& A, double R) -> array<double, 2> {
        // y^2 = 0, 
        // y^2 = R^2 - (x - A.x)^2 + 2yA.y - A.y ^ 2;
        // R^2 - (x - A.x) ^ 2 - A.y^2 = 0
        // R^2 - x^2 + 2xA.x - A.x^2 - A.y^2 = 0
        // x^2 - 2xA.x + A.x^2 + A.y^2 - R^2 = 0
        // D = -4A.y^2 + 4R^2
        if(abs(A.y) > R) {
            return {L, -1};
        }
        double D = 4 * (R * R - A.y * A.y);
        double x1 = (2 * A.x - sqrt(D)) / 2;
        double x2 = (2 * A.x + sqrt(D)) / 2;
        if(x2 < x1) swap(x1, x2);
        if(x1 < 0) x1 = 0; 
        if(x2 > L) x2 = L;
        return {x1, x2};
    };

    auto good = [&](double R) {
        vector<array<double, 2>> segs(n);
        for(int i = 0; i < n; i++) {
            segs[i] = intersection(p[i], R);
        }
        sort(segs.begin(), segs.end());
        double l = segs[0][0], r = segs[0][1];
        int i = 0;
        while(i + 1 < n && segs[i + 1][0] <= r) {
            r = max(segs[i + 1][1], r);
            i++;
        }
        return r >= L && l <= 0;
    };

    double l = -1, r = 1;
    while(!good(r)) r *= 2;
    while(r - l > eps) {
        double R = (r + l) / 2;
        if(good(R)) {
            r = R;
        }
        else {
            l = R;
        }
        
    }
    cout << fixed << setprecision(6) << r << endl;
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    double T = 1;
    //cin >> T;
    while(T--) solve();
    return 0;
}

Subtask #1
0 / 4.0

# Verdict Execution time Memory Grader output
1 Incorrect 0 ms 344 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
0 / 4.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 348 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
0 / 4.0

# Verdict Execution time Memory Grader output
1 Incorrect 3 ms 348 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 4.0

# Verdict Execution time Memory Grader output
1 Incorrect 8 ms 604 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #5
0 / 4.0

# Verdict Execution time Memory Grader output
1 Incorrect 8 ms 604 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #6
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 6 ms 600 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #7
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 133 ms 2784 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #8
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 149 ms 2908 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #9
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 129 ms 3164 KB Output is correct
2 Correct 236 ms 2908 KB Output is correct
3 Correct 184 ms 2908 KB Output is correct
4 Incorrect 365 ms 3408 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #10
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 304 ms 3420 KB Output is correct
2 Correct 299 ms 3564 KB Output is correct
3 Correct 207 ms 3568 KB Output is correct
4 Incorrect 359 ms 3412 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #11
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 301 ms 3568 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #12
0 / 5.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1063 ms 16076 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #13
0 / 5.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1058 ms 16076 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #14
0 / 5.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1058 ms 19148 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #15
0 / 5.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1052 ms 19120 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #16
0 / 5.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1022 ms 22420 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #17
0 / 5.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1050 ms 22220 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #18
0 / 5.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1045 ms 25468 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #19
0 / 5.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1026 ms 25464 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #20
0 / 5.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1058 ms 31572 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #21
0 / 5.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1058 ms 31572 KB Time limit exceeded
2 Halted 0 ms 0 KB -