Submission #470002

#	Time	Username	Problem	Language	Result	Execution time	Memory
470002		Shogun3103	Mobile (BOI12_mobile)	C++17	12 / 100	709 ms	19012 KiB

mobile

#include <bits/stdc++.h>
 
using namespace std;

void setIO(string fileName = ""){
    ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);        
    if(fileName.length()){
        freopen((fileName+".in").c_str(), "r", stdin);
        freopen((fileName+".out").c_str(), "w", stdout);
    }
}

#define ll long long
#define ld long double
#define FOR(i,a,b) for(__typeof(b) i=a; i<=b; i++)
#define FOD(i,a,b) for(__typeof(b) i=b; i>=a; i--)
#define EACH(u, v) for(auto& u : v)
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define ii pair<int,int>
#define iii pair<int,ii>
#define ld2 pair<ld, ld>
#define ll2 pair<ll, ll>
#define X first
#define Y second
#define ed "\n"
#define sp " "
const int oo = 1e9 + 7;
const int N = 1e6 + 10;

int n, len;
ii a[N];
ld cur;

bool calc(ld x)
{   
    FOR(i, 1, n) {
        ld delta = sqrt(x * x - a[i].Y * a[i].Y);
        ld x = a[i].X - delta, y = a[i].X + delta;
        if(x <= cur) cur = max(cur, y);
    }   
    return cur >= len;
}

void solve()
{
    cin >> n >> len;
    FOR(i, 1, n) cin >> a[i].X >> a[i].Y;

    ld l = 1, r = 1.5e9;
    while(l <= r) {
        ld m = (l + r) * 0.5;
        cur = 0;
        if(calc(m)) {
            r = m - 0.0001;
        } else {
            l = m + 0.0001;
        }
    }
    cout << fixed << setprecision(6) << r; 
}   

int main()
{ 
    setIO("");
    int t; 
    t = 1;
    //cin >> t;
    FOR(i, 1, t) {
        solve();
    }
    return 0;
}

Compilation message (stderr)

mobile.cpp: In function 'void setIO(std::string)':
mobile.cpp:8:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    8 |         freopen((fileName+".in").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mobile.cpp:9:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    9 |         freopen((fileName+".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
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