Submission #1198119

#	Time	Username	Problem	Language	Result	Execution time	Memory
1198119		cpismylifeOwO	Mobile (BOI12_mobile)	C++20	100 / 100	647 ms	16208 KiB

mobile

#include <bits/stdc++.h>

using namespace std;

const long long mod = 1e9 + 7;
const int MaxN = 1e6 + 5;

int n;
long long l;
pair<long long, long long> arr[MaxN];

void Inp()
{
    cin >> n >> l;
    for (int x = 1; x <= n; x++)
    {
        cin >> arr[x].first >> arr[x].second;
    }
    sort(arr + 1, arr + n + 1);
}

int i;
pair<long double, long double> st[MaxN];

bool Check(long double k)
{
    i = -1;
    for (int x = 1; x <= n; x++)
    {
        if (abs(arr[x].second) > k)
        {
            continue;
        }
        long double a = arr[x].first, b = arr[x].second;
        long double p = sqrt(k * k - b * b), l = a - p, r = a + p;
        while (i >= 0 && max(l, st[i].first) <= min(r, st[i].second))
        {
            l = min(l, st[i].first);
            r = max(r, st[i].second);
            i--;
        }
        i++;
        st[i] = make_pair(l, r);
    }
    for (int x = 0; x <= i; x++)
    {
        if (st[x].first <= 0 && l <= st[x].second)
        {
            return true;
        }
    }
    return false;
}

void Exc()
{
    long long l = 0, r = 1e14, mid, res = 1e14;
    while (l <= r)
    {
        mid = (l + r) / 2;
        if (Check((long double)mid / 10000.0))
        {
            res = mid;
            r = mid - 1;
        }
        else
        {
            l = mid + 1;
        }
    }
    cout << fixed << setprecision(4) << (long double)res / 10000.0;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int test = 1;
    //cin >> test;
    for (int x = 1; x <= test; x++)
    {
        Inp();
        Exc();
    }
    return 0;
}

• Subtask 1: 4 / 4
• Subtask 2: 4 / 4
• Subtask 3: 4 / 4
• Subtask 4: 4 / 4
• Subtask 5: 4 / 4
• Subtask 6: 5 / 5
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• Subtask 19: 5 / 5
• Subtask 20: 5 / 5
• Subtask 21: 5 / 5