Submission #713017

#	Time	Username	Problem	Language	Result	Execution time	Memory
713017		Ahmed57	Mobile (BOI12_mobile)	C++14	90 / 100	1081 ms	16140 KiB

mobile

#include <bits/stdc++.h>

using namespace std;
pair<double,double> cordinates[1000001];
int n;double l;
bool ch(double mid){
    double cur = 0,x,begi,en;
    for(int i =0;i<n;i++){
        if(cordinates[i].second>mid)continue;
        x = sqrt((mid*mid)-(cordinates[i].second*cordinates[i].second));
        begi = cordinates[i].first-x;
        en = cordinates[i].first+x;
        if(begi<=cur)cur = max(cur,en);
    }
    return (cur>=l);
}
int main(){
    ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    cin>>n>>l;
    for(int i = 0;i<n;i++){
        cin>>cordinates[i].first>>cordinates[i].second;
    }
    double l = 0.0 ,r = 1000000000.0;
    for(int i = 0;i<75;i++){
        double mid=(l+r)/2.0;
        if(ch(mid))r = mid;
        else l = mid;
    }
    cout<<setprecision(9)<<fixed<<r<<endl;
}

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