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Submission #873850

# Submission time Handle Problem Language Result Execution time Memory
873850 2023-11-16T01:19:51 Z perohero Mobile (BOI12_mobile) C++17
100 / 100
 242 ms 35468 KB 
#include <bits/stdc++.h>
#define int long long

using i64 = long long;
using ld = long double;

ld cross(std::pair<int, int> a, std::pair<int, int> b) {
    int x1 = a.first, x2 = b.first, y1 = a.second, y2 = b.second;
    return 1.0 * (1ll * x2 * x2 + y2 * y2 - 1ll * x1 * x1 - 1ll * y1 * y1) / (2.0 * (x2 - x1));
}

ld solve(ld s, ld e, std::pair<int, int> t) {
    return std::max(std::hypot(s - t.first, t.second), std::hypot(e - t.first, t.second));
}

signed main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    std::cout << std::fixed << std::setprecision(3);

    int n, L;
    std::cin >> n >> L;
    std::vector<std::pair<int, int>> a(n);
    for (int i = 0; i < n; i++) {
        std::cin >> a[i].first >> a[i].second;
        a[i].second = abs(a[i].second);
    }
    std::sort(a.begin(), a.end());
    std::deque<std::pair<int, int>> st;
    for (int i = 0; i < n; i++) {
        int j = i;
        while (j < n && a[j].first == a[i].first) {
            j++;
        }
        while (st.size() >= 2 && cross(st[st.size() - 2], st.back()) > cross(st.back(), a[i])) {
            st.pop_back();
        }
        st.push_back(a[i]);
        i = j - 1;
    }

    ld answer = 0;
    while (st.size() >= 2 && cross(st[0], st[1]) < 0) {
        st.pop_front();
    }
    while (st.size() >= 2 && cross(st[st.size() - 2], st.back()) > L) {
        st.pop_back();
    }
    answer = std::max(answer, solve(0, cross(st[0], st[1]), st[0]));
    answer = std::max(answer, solve(cross(st[st.size() - 2], st.back()), L, st.back()));
    for (int i = 1; i < st.size() - 1; i++) {
        answer = std::max(answer, solve(cross(st[i - 1], st[i]), cross(st[i], st[i + 1]), st[i]));
    }
    answer = (ld) ((ld) ((ld) answer * (int) 1e3) / (int) 1e3);
    std::cout << answer << "\n";
    return 0;
}

Compilation message

mobile.cpp: In function 'int main()':
mobile.cpp:52:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::deque<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   52 |     for (int i = 1; i < st.size() - 1; i++) {
      |                     ~~^~~~~~~~~~~~~~~

Subtask #1
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 348 KB Output is correct

Subtask #2
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 348 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 1 ms 348 KB Output is correct

Subtask #4
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 1 ms 548 KB Output is correct
4 Correct 2 ms 348 KB Output is correct

Subtask #5
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 600 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 1 ms 348 KB Output is correct
4 Correct 1 ms 348 KB Output is correct

Subtask #6
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 1 ms 348 KB Output is correct
4 Correct 1 ms 348 KB Output is correct
5 Correct 1 ms 348 KB Output is correct

Subtask #7
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 1624 KB Output is correct
2 Correct 12 ms 1628 KB Output is correct
3 Correct 9 ms 1884 KB Output is correct
4 Correct 15 ms 2784 KB Output is correct
5 Correct 7 ms 1556 KB Output is correct

Subtask #8
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 1624 KB Output is correct
2 Correct 12 ms 1368 KB Output is correct
3 Correct 14 ms 1628 KB Output is correct
4 Correct 17 ms 2848 KB Output is correct
5 Correct 18 ms 3164 KB Output is correct

Subtask #9
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 3360 KB Output is correct
2 Correct 15 ms 1628 KB Output is correct
3 Correct 17 ms 3928 KB Output is correct
4 Correct 22 ms 3936 KB Output is correct
5 Correct 14 ms 2652 KB Output is correct

Subtask #10
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 20 ms 1884 KB Output is correct
2 Correct 17 ms 3428 KB Output is correct
3 Correct 15 ms 3164 KB Output is correct
4 Correct 21 ms 4184 KB Output is correct
5 Correct 18 ms 3164 KB Output is correct

Subtask #11
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 20 ms 2904 KB Output is correct
2 Correct 19 ms 1912 KB Output is correct
3 Correct 15 ms 3164 KB Output is correct
4 Correct 21 ms 3796 KB Output is correct
5 Correct 18 ms 3160 KB Output is correct

Subtask #12
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 127 ms 16608 KB Output is correct
2 Correct 78 ms 8284 KB Output is correct
3 Correct 76 ms 8284 KB Output is correct
4 Correct 97 ms 8284 KB Output is correct
5 Correct 89 ms 14932 KB Output is correct

Subtask #13
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 85 ms 8284 KB Output is correct
2 Correct 81 ms 9048 KB Output is correct
3 Correct 71 ms 9808 KB Output is correct
4 Correct 99 ms 17496 KB Output is correct
5 Correct 88 ms 15448 KB Output is correct

Subtask #14
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 143 ms 19684 KB Output is correct
2 Correct 93 ms 9816 KB Output is correct
3 Correct 90 ms 9836 KB Output is correct
4 Correct 124 ms 10068 KB Output is correct
5 Correct 104 ms 17748 KB Output is correct

Subtask #15
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 95 ms 9816 KB Output is correct
2 Correct 97 ms 10608 KB Output is correct
3 Correct 80 ms 10836 KB Output is correct
4 Correct 120 ms 9848 KB Output is correct
5 Correct 109 ms 18532 KB Output is correct

Subtask #16
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 170 ms 22752 KB Output is correct
2 Correct 126 ms 11404 KB Output is correct
3 Correct 108 ms 11404 KB Output is correct
4 Correct 137 ms 11404 KB Output is correct
5 Correct 118 ms 20240 KB Output is correct

Subtask #17
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 115 ms 11356 KB Output is correct
2 Correct 115 ms 12176 KB Output is correct
3 Correct 101 ms 13396 KB Output is correct
4 Correct 143 ms 24660 KB Output is correct
5 Correct 130 ms 21936 KB Output is correct

Subtask #18
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 191 ms 26104 KB Output is correct
2 Correct 131 ms 12972 KB Output is correct
3 Correct 123 ms 12888 KB Output is correct
4 Correct 161 ms 12976 KB Output is correct
5 Correct 141 ms 24148 KB Output is correct

Subtask #19
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 130 ms 12892 KB Output is correct
2 Correct 129 ms 14000 KB Output is correct
3 Correct 113 ms 14764 KB Output is correct
4 Correct 163 ms 28240 KB Output is correct
5 Correct 141 ms 24436 KB Output is correct

Subtask #20
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 242 ms 32504 KB Output is correct
2 Correct 159 ms 15964 KB Output is correct
3 Correct 151 ms 16100 KB Output is correct
4 Correct 204 ms 35152 KB Output is correct
5 Correct 174 ms 29560 KB Output is correct

Subtask #21
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 168 ms 15960 KB Output is correct
2 Correct 162 ms 17128 KB Output is correct
3 Correct 153 ms 18516 KB Output is correct
4 Correct 204 ms 35468 KB Output is correct
5 Correct 200 ms 30544 KB Output is correct