Submission #305634

#	Time	Username	Problem	Language	Result	Execution time	Memory
305634		ant101	Mobile (BOI12_mobile)	C++14	100 / 100	912 ms	51936 KiB

mobile

#include <iostream>
#include <algorithm>
#include <cstring>
#include <iomanip>
#include <fstream>
#include <cmath>
#include <vector>
#include <set>
#include <unordered_set>
#include <unordered_map>
#include <map>
#include <stack>
#include <queue>
#include <assert.h>
#include <limits>
#include <cstdio>
#include <complex>
using namespace std;


#define rep(x,a)           for(int x = 0; x < a; x++)
#define REP(x,a,b)         for(int x = a; x < b; x++)
#define per(x,b)           for(int x = b; x >= 0; x--)
#define all(container)     (container).begin(), container.end()
#define rall(container)    (container).rbegin(), container.rend()
#define sz(container)      (int) (container).size()
#define pb                 push_back
#define eb                 emplace_back
#define fi                 first
#define sc                 second

using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

template<class T> bool smin(T &a, T b) { return a > b ? (a = b, true) : false; }
template<class T> bool smax(T &a, T b) { return a < b ? (a = b, true) : false; }

#ifdef LOCAL_DEFINE
#include "DEBUG.hpp"
#else
#define debug(...) 0
#endif

const double eps = 1e-3;
const double EPS = 1e-9;

bool eq(double a, double b) {
    return abs(a-b) <= eps;
}

int main(void)
{
    int n;
    double last;
    scanf("%d%lf", &n, &last);
    vector<pair<double, double>> points(n);
    rep(i,n) scanf("%lf%lf", &points[i].fi, &points[i].sc);
    vector<pair<double, double>> poi;
    rep(i,n) {
        poi.emplace_back(points[i]);
        ++i;
        while (i < n && eq(points[i].fi, poi.back().fi)) ++i;
        --i;
    }
    auto Can = [&](double dist) {
        double r = 0.0;
        rep(i,n) {
            double delta = sqrt(dist*dist-points[i].sc*points[i].sc);
            double L = points[i].fi-delta, R = points[i].fi+delta;
            if (L <= r) smax(r, R);
        }
        return (r >= last);
    };
    double l = 0.0, r = 1e10;
    while (r-l > eps) {
        double mid = (r+l)/2.0;
        if (Can(mid)) r = mid;
        else l = mid;
    }
    printf("%.6lf\n", l);
    return 0;
}

Compilation message (stderr)

mobile.cpp: In function 'int main()':
mobile.cpp:56:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   56 |     scanf("%d%lf", &n, &last);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~
mobile.cpp:58:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   58 |     rep(i,n) scanf("%lf%lf", &points[i].fi, &points[i].sc);
      |              ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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