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Submission #623058

# Submission time Handle Problem Language Result Execution time Memory
623058 2022-08-05T06:44:02 Z 54skyxenon Mobile (BOI12_mobile) C++17
8 / 100
 1000 ms 48148 KB 
// https://oj.uz/problem/view/BOI12_mobile

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

#define pdd pair<double, double>
#define mp make_pair

int n, l;
vector<double> X, Y;

vector<pdd> merge(vector<pdd>& intervals) {
    sort(intervals.begin(), intervals.end());

    vector<pdd> new_intervals;
    for (auto [start, end] : intervals) {
        if (new_intervals.empty() || new_intervals.rbegin()->second < start) {
            new_intervals.push_back(mp(start, end));
        }
        else {
            new_intervals.rbegin()->second = max(new_intervals.rbegin()->second, end);
        }
    }
    
    return new_intervals;
}

bool ok(double radius) {
    vector<pdd> intervals({mp(0, 0), mp(l, l)});
    
    for (int i = 0; i < n; i++) {
        double x1 = X[i], y1 = Y[i];
    
        double term = (radius * radius) - (y1 * y1);
        if (term >= 0) {
            double term_sqrt = sqrt(term);
            intervals.push_back(mp(x1 - term_sqrt, x1 + term_sqrt));
        }
    }
        
    intervals = merge(intervals);

    for (int i = 0; i < intervals.size() - 1; i++) {
        double midpt = (intervals[i].second + intervals[i + 1].first) / 2;
        if (0 <= midpt && midpt <= l) {
            return true;
        }
    }

    return false;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    
    cin >> n >> l;

    X.resize(n);
    Y.resize(n);
    for (int i = 0; i < n; i++) {
        cin >> X[i] >> Y[i];
    }

    double lo = 0.0;
    double hi = l;

    int threshold = 1000;
    while (threshold--) {
        double mid = (lo + hi) / 2;

        if (!ok(mid)) {
            hi = mid;
        }
        else {
            lo = mid;
        }
    }

    cout << lo << endl;
}

Compilation message

mobile.cpp: In function 'bool ok(double)':
mobile.cpp:43:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<double, double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |     for (int i = 0; i < intervals.size() - 1; i++) {
      |                     ~~^~~~~~~~~~~~~~~~~~~~~~

Subtask #1
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct

Subtask #2
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 5 ms 328 KB Output is correct
4 Correct 3 ms 212 KB Output is correct

Subtask #3
0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 340 KB Output is correct
2 Correct 67 ms 468 KB Output is correct
3 Correct 7 ms 388 KB Output is correct
4 Incorrect 102 ms 444 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #4
0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 468 KB Output is correct
2 Incorrect 160 ms 612 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #5
0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 504 KB Output is correct
2 Incorrect 160 ms 664 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #6
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 284 ms 624 KB Output is correct
2 Incorrect 159 ms 612 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #7
0 / 5.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1094 ms 4740 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #8
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 160 ms 2696 KB Output is correct
2 Correct 146 ms 2584 KB Output is correct
3 Incorrect 158 ms 2736 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #9
0 / 5.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1089 ms 5280 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #10
0 / 5.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1091 ms 5684 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #11
0 / 5.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1087 ms 5668 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #12
0 / 5.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1096 ms 24244 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 1093 ms 24444 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 1093 ms 35560 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 1099 ms 35716 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 1084 ms 38760 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 1098 ms 38680 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 1096 ms 41836 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 1093 ms 41852 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 1091 ms 48032 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 1057 ms 48148 KB Time limit exceeded
2 Halted 0 ms 0 KB -