Submission #684149

#	Time	Username	Problem	Language	Result	Execution time	Memory
684149		ThisWasUnplanned	Mobile (BOI12_mobile)	C++17	0 / 100	745 ms	33316 KiB

mobile

/*
⡆⣐⢕⢕⢕⢕⢕⢕⢕⢕⠅⢗⢕⢕⢕⢕⢕⢕⢕⠕⠕⢕⢕⢕⢕⢕⢕⢕⢕⢕
⢐⢕⢕⢕⢕⢕⣕⢕⢕⠕⠁⢕⢕⢕⢕⢕⢕⢕⢕⠅⡄⢕⢕⢕⢕⢕⢕⢕⢕⢕
⢕⢕⢕⢕⢕⠅⢗⢕⠕⣠⠄⣗⢕⢕⠕⢕⢕⢕⠕⢠⣿⠐⢕⢕⢕⠑⢕⢕⠵⢕
⢕⢕⢕⢕⠁⢜⠕⢁⣴⣿⡇⢓⢕⢵⢐⢕⢕⠕⢁⣾⢿⣧⠑⢕⢕⠄⢑⢕⠅⢕
⢕⢕⠵⢁⠔⢁⣤⣤⣶⣶⣶⡐⣕⢽⠐⢕⠕⣡⣾⣶⣶⣶⣤⡁⢓⢕⠄⢑⢅⢑
⠍⣧⠄⣶⣾⣿⣿⣿⣿⣿⣿⣷⣔⢕⢄⢡⣾⣿⣿⣿⣿⣿⣿⣿⣦⡑⢕⢤⠱⢐
⢠⢕⠅⣾⣿⠋⢿⣿⣿⣿⠉⣿⣿⣷⣦⣶⣽⣿⣿⠈⣿⣿⣿⣿⠏⢹⣷⣷⡅⢐
⣔⢕⢥⢻⣿⡀⠈⠛⠛⠁⢠⣿⣿⣿⣿⣿⣿⣿⣿⡀⠈⠛⠛⠁⠄⣼⣿⣿⡇⢔
⢕⢕⢽⢸⢟⢟⢖⢖⢤⣶⡟⢻⣿⡿⠻⣿⣿⡟⢀⣿⣦⢤⢤⢔⢞⢿⢿⣿⠁⢕
⢕⢕⠅⣐⢕⢕⢕⢕⢕⣿⣿⡄⠛⢀⣦⠈⠛⢁⣼⣿⢗⢕⢕⢕⢕⢕⢕⡏⣘⢕
⢕⢕⠅⢓⣕⣕⣕⣕⣵⣿⣿⣿⣾⣿⣿⣿⣿⣿⣿⣿⣷⣕⢕⢕⢕⢕⡵⢀⢕⢕
⢑⢕⠃⡈⢿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⢃⢕⢕⢕
⣆⢕⠄⢱⣄⠛⢿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠿⢁⢕⢕⠕⢁
⣿⣦⡀⣿⣿⣷⣶⣬⣍⣛⣛⣛⡛⠿⠿⠿⠛⠛⢛⣛⣉⣭⣤⣂⢜⠕⢑⣡⣴⣿
*/
#include <bits/stdc++.h>

using namespace std;

typedef long long LL;
typedef long double LD;
#define MAX 100
#define pi acos(-1)
#define whatis(x) cout << #x << " is " << x << "\n";
#define all(x) x.begin(), x.end()
#define endl "\n"
#define DEB cout << "TESTING" NL
#define TESTS int test; cin>>test; for(int kase = 1 ; kase <= test ; kase++) solve(kase);
#define CASEOUT cout << "Case " << testcase << ": " << 
#define YESNO cout << (possible? "YES\n" : "NO\n");
// #define YES cout << "YES\n";
// #define NO cout << "NO\n";
#define int long long
#define pii pair<int,int>

LD distance(pair<LD, LD> a, pair<LD, LD> b)
{
    return (a.first - b.first) * (a.first - b.first) + (a.second - b.second) * (a.second - b.second);
}

LD ternary(pair<LD, LD> a, pair<LD, LD> b)
{
    LD low = a.first, high = b.first;
    LD mid1, mid2, mid3;
    do{
        mid2 = low + (high - low)/2;
        mid1 = low + (mid2 - low)/2;
        mid3 = mid2 + (high - mid2)/2;
        if(min(distance({mid1, 0}, a), distance({mid1, 0}, b)) < min(distance({mid3, 0}, a), distance({mid3, 0}, b)))
        {
            low = mid2;
        }
        else high = mid2;
    } while(abs(mid2 - mid3) > 1e-4);
    return mid2;
}

int solve(int testcase)
{
    int n;
    LD l;
    cin >> n >> l;
    vector <pair <LD, LD>> towers;
    for(int i = 0; i < n; i++)
    {
        LD x, y;
        cin >> x >> y;
        if(!towers.size() || towers.back().first != x)
            towers.push_back({x, y});
    }
    LD res = -1;
    // for(int i = 0 ; i < towers.size()-1 ; i++)
    // {
    //     if(towers[i].first < 0 && towers[i+1].first > 0)
    //     {
    //         res = max(res, distance({0, 0}, towers[i]));
    //         res = max(res, distance({0, 0}, towers[i+1]));
    //     }
    //     if(towers[i].first < l && towers[i+1].first > l)
    //     {
    //         res = max(res, distance({l, 0}, towers[i]));
    //         res = max(res, distance({l, 0}, towers[i+1]));
    //     }
    // }
    // if(res != -1) res = sqrt(res);
    for(int i = 0 ; i < towers.size()-1 ; i++)
    {
        LD point = ternary(towers[i], towers[i+1]);
        res = max({res, distance({point, 0}, towers[i]), distance({point, 0}, towers[i+1])});
    }
    cout << fixed << setprecision(6) << sqrt(res) << endl;
    return 0;
}

signed main()
{
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    //cout.tie(NULL);

    solve(0);
    // TESTS
    return 0;
}

Compilation message (stderr)

mobile.cpp: In function 'long long int solve(long long int)':
mobile.cpp:87:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long double, long double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   87 |     for(int i = 0 ; i < towers.size()-1 ; i++)
      |                     ~~^~~~~~~~~~~~~~~~~

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