Submission #1213156

#	Time	Username	Problem	Language	Result	Execution time	Memory
1213156		Madhav_1608	Mobile (BOI12_mobile)	C++20	100 / 100	485 ms	47412 KiB

mobile

#include <iostream>
#include <stack>
#include <queue>
#include <string>
#include <algorithm>
#include <vector>
#include <map>
#include <set>
#include <climits>
#include <cmath>
#include <unordered_map>
#include <unordered_set>
#include <numeric>
#include <iomanip>
#include <cstring>
#include <stdio.h>
#include <assert.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<string> vs;
typedef vector<long long> vll;
typedef pair<ll,ll> pll;
#define double long double
#define F first
#define S second
const double eps = 1e-4; 
#define FOR(i,a,b) for(long long i=a;i<b;i++)
#define all(v) v.begin(),v.end()
template <typename I>
void print(vector<I> &v){
    FOR(i,0,v.size()){cout << v[i] << " ";}
    cout << "\n";
}
ll gcd(ll a,ll b){
    if(a==0){return b;}
    else if(b==0){return a;}
    else if(a<b){return gcd(b%a,a);}
    else{return gcd(a%b,b);}
}
ll lcm(ll a,ll b){
    return (a/gcd(a,b))*b;
}
void setIO(string name = "") {
    freopen((name + ".in").c_str(), "r", stdin); // see /general/input-output
    freopen((name + ".out").c_str(), "w", stdout);
}
void init_code(){
    #ifndef ONLINE_JUDGE
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
    #endif
}
ll n;
double l;
pair<double,double> towers[1000001];
double sqrs[1000001];
bool func(double r){
    double small = 1.5e9;
    double large = 0;
    double sqr_r = r*r;
    FOR(i,0,n){
        if((r<towers[i].S)) continue;
        double bnd = sqrtl(sqr_r-sqrs[i]);
        double left = towers[i].F-bnd;
        double right = towers[i].F+bnd;
        if(left<=large){
            small = min(small,left);
            large = max(large,right);
        }
    }
    if(small>0) return false;
    if(large<l) return false;
    return true;
}
void solve(){
    // store very big numbers may mean log2.
    // A comparator must return false for two equal objects. Not doing so results in undefined behavior.
    cin >> n >> l;
    FOR(i,0,n){
        double x,y;
        cin >> x >> y;
        y = abs(y);
        towers[i] = {x,y};
        sqrs[i] = y*y;
    }
    double left = 0;
    double right = 1.5e9;
    while((right-left)>eps){
        double mid = (left+right)/(double)2;
        if(func(mid)){
            right = mid;
        }
        else{
            left = mid;
        }
    }
    cout << setprecision(12) << right << "\n";
}

signed main(){
    //setIO
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    // init_code();
    ll t=1;
    // cin >> t;
    while(t--){
        solve();
    }
    return 0;
}

Compilation message (stderr)

mobile.cpp: In function 'void setIO(std::string)':
mobile.cpp:45:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |     freopen((name + ".in").c_str(), "r", stdin); // see /general/input-output
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mobile.cpp:46:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |     freopen((name + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mobile.cpp: In function 'void init_code()':
mobile.cpp:50:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   50 |     freopen("input.txt","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
mobile.cpp:51:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |     freopen("output.txt","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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