Submission #1241304

#	Time	Username	Problem	Language	Result	Execution time	Memory
1241304		Zero	Mobile (BOI12_mobile)	C++20	100 / 100	759 ms	15944 KiB

mobile

#include <bits/stdc++.h>
#define f first
#define ss second
using namespace std;
vector<pair<double,double>> a;
int n;
double L;
bool ok(double m){
    double cr = 0;
    for(int i=0; i < n; i ++){
        double xx = sqrt(m*m-a[i].ss*a[i].ss);
        double le = a[i].f - xx, re = a[i].f + xx;
        if(le <= cr) cr = max(cr,re);
    }
    return cr >= L;
}

signed main(){
    cin.tie(0)->sync_with_stdio(0);
    cin >> n >> L;
    a.resize(n);
    for(auto &i : a) cin >> i.first >> i.second;
    
    double l = -1, r = 1e9;
    for(int i=0; i < 100; i ++){
        double m = (l+r)/2;
        if(ok(m)) r = m;
        else l=m;
    }
    cout << fixed << setprecision(6) << r;
}

• Subtask 1: 4 / 4
• Subtask 2: 4 / 4
• Subtask 3: 4 / 4
• Subtask 4: 4 / 4
• Subtask 5: 4 / 4
• Subtask 6: 5 / 5
• Subtask 7: 5 / 5
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• Subtask 10: 5 / 5
• Subtask 11: 5 / 5
• Subtask 12: 5 / 5
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• Subtask 14: 5 / 5
• Subtask 15: 5 / 5
• Subtask 16: 5 / 5
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• Subtask 18: 5 / 5
• Subtask 19: 5 / 5
• Subtask 20: 5 / 5
• Subtask 21: 5 / 5