Submission #465489

#	Time	Username	Problem	Language	Result	Execution time	Memory
465489		tphuc2908	Mobile (BOI12_mobile)	C++14	0 / 100	688 ms	41136 KiB

mobile

#include<bits/stdc++.h>

using namespace std;
#define rep(i, x, y) for(int i = x; i <= y; ++i)
#define repi(i,x,y) for(int i = x; i >= y; --i)
#define ci(x) int x; cin>> x
#define TC(t) ci(t); while(t--)
#define fi first
#define se second
#define pb push_back
#define all(x) x.begin(), x.end()
#define cii(x, y) ci(x); ci(y)
typedef long long ll;
typedef vector<int> vi;
const int N = 1e6 + 5;
const int mod = 1e9+7;
const int inf = 1e9 + 5;

void readfile(){
    #ifdef ONLINE_JUDGE
    #else
        freopen("text.inp", "r", stdin);
    #endif // ONLINE_JUDGE
//    freopen("angry.in", "r", stdin);
//    freopen("angry.out", "w", stdout);
}

int n;
int L;
pair<double, double> a[N];
vector<pair<double, double> > store;

void inp(){
    cin >> n >> L;
    rep(i,1,n){
        cii(x, y);
        a[i] = {double(x), double(y)};
    }
}

void trim(){
    rep(i,1,n){
        if(i==1 || a[i].fi != a[i-1].fi)
            store.pb(a[i]);
    }
}

void process(){
    trim();
    if((int)store.size()==1){
        cout << max(sqrt((store[0].fi-L)*(store[0].fi-L) + store[0].se*store[0].se), sqrt(store[0].fi*store[0].fi + store[0].se*store[0].se));
        return;
    }
    double res = 0;
    if(0 <= a[0].fi)
        res = sqrt(a[0].fi*a[0].fi + a[0].se*a[0].se);
    rep(i,0,(int)store.size()-2){
        double l = store[i].fi, r = store[i+1].fi;
        rep(j,1,30){
            double mid = (l + r) / 2;
            double cal1 = sqrt((mid-store[i].fi)*(mid-store[i].fi) + store[i].se*store[i].se);
            double cal2 = sqrt((mid-store[i+1].fi)*(mid-store[i+1].fi) + store[i+1].se*store[i+1].se);
            res = max(res, min(cal1, cal2));
            if(cal1 <= cal2)
                l = mid;
            else r = mid;
        }
    }
    if(L >= store.back().fi)
        res = max(res, sqrt((store.back().fi - L)*(store.back().fi - L) + store.back().se*store.back().se));
    cout << res;
}

int main(){
    //readfile();
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    inp();
    process();
    return 0;
}

Compilation message (stderr)

mobile.cpp: In function 'void readfile()':
mobile.cpp:22:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   22 |         freopen("text.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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