Submission #1283289

#	Time	Username	Problem	Language	Result	Execution time	Memory
1283289		vahagng	Odašiljači (COCI20_odasiljaci)	C++20	42 / 70	1096 ms	580 KiB

odasiljaci

//----------vahagng----------//
#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
using namespace std;
// using namespace __gnu_pbds;

// template <class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x <<" "; print(x); cerr << endl;
#else
#define dbg(x)
#endif

void print(long long t) { cerr << t; }
void print(int t) { cerr << t; }
void print(string t) { cerr << t; }
void print(char t) { cerr << t; }
void print(double t) { cerr << t; }
void print(long double t) { cerr << t; }
void print(unsigned long long t) { cerr << t; }

template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(T v[], V n) { cerr << "["; for (int i = 0; i < n; i++) { cerr << v[i] << " "; } cerr << "]"; }
template <class T, class V> void print(pair <T, V> p) { cerr << "{"; print(p.first); cerr << ","; print(p.second); cerr << "}"; }
template <class T> void print(vector <T> v) { cerr << "[ "; for (T i : v) { print(i); cerr << " "; } cerr << "]"; }
template <class T> void print(set <T> v) { cerr << "[ "; for (T i : v) { print(i); cerr << " "; } cerr << "]"; }
template <class T> void print(multiset <T> v) { cerr << "[ "; for (T i : v) { print(i); cerr << " "; } cerr << "]"; }
template <class T, class V> void print(map <T, V> v) { cerr << "[ "; for (auto i : v) { print(i); cerr << " "; } cerr << "]"; }

#define ll long long
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define ld long double
#define sz(v) v.size()
#define endl '\n'

const ll inf = 2e18, mod = 1e9 + 7, mod2 = 998244353;

void SetIO(string str = "") {
    if (str != "") {
        freopen((str + ".in").c_str(), "r", stdin);
        freopen((str + ".out").c_str(), "w", stdout);
    }
    else {
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    }
}

void FastIO() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
}

const int N = 2e5 + 10, M = 1e7 + 10;

mt19937 rnd(chrono::system_clock::now().time_since_epoch().count());

ll binpow(ll a, ll b, ll m) {
    ll res = 1;
    while (b) {
        if (b & 1) {
            res = (res * a) % m;
        }
        b >>= 1;
        a = (a * a) % m;
    }
    return res;
}

int n, x[N], y[N];

struct DSU{
    int par[N], sz[N], comps;

    void init(){
        comps = n;
        for(int i = 1; i <= n; i++){
            par[i] = i;
            sz[i] = 1;
        }
    }

    int find(int a){
        if(par[a] == a) return a;
        return par[a] = find(par[a]);
    }

    bool merge(int a, int b){
        a = find(a), b = find(b);
        if(a == b) return 0;
        comps--;
        if(sz[a] > sz[b]) swap(a, b);
        sz[b] += sz[a];
        sz[a] = 0;
        par[a] = b;
        return 1;
    }
}dsu;

bool check(double r){
    dsu.init();
    for(int i = 1; i <= n; i++){
        for(int j = i+1; j <= n; j++){
            double d = (x[i] - x[j])*(x[i] - x[j]) + (y[i] - y[j])*(y[i] - y[j]);
            if(d <= 4*r*r){
                dsu.merge(i, j);
            }
        }
    }
    return dsu.comps == 1;
}

void solve(int tc) {
    cin >> n;
    for(int i = 1; i <= n; i++){
        cin >> x[i] >> y[i];
    }
    double l = 0, r = 1e9, ans;
    for(int it = 0; it < 350; it++){
        double m = (l + r)/2;
        if(check(m)){
            ans = m;
            r = m;
        }else{
            l = m;
        }
    }
    cout << fixed << setprecision(20) << ans << endl;
}


void precalc() {

}

int main() {
    // SetIO("teamwork");
    FastIO();
    int test_case = 1;
    // cin >> test_case;
    precalc();
    int cnt = 1;
    while (test_case--) {
        solve(cnt++);
    }
    return 0;
}

Compilation message (stderr)

odasiljaci.cpp: In function 'void SetIO(std::string)':
odasiljaci.cpp:47:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   47 |         freopen((str + ".in").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
odasiljaci.cpp:48:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   48 |         freopen((str + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
odasiljaci.cpp:51:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |         freopen("input.txt", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
odasiljaci.cpp:52:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   52 |         freopen("output.txt", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 42 / 70