Submission #1352054

#TimeUsernameProblemLanguageResultExecution timeMemory
1352054chithanhnguyenOdašiljači (COCI20_odasiljaci)C++20
70 / 70
71 ms452 KiB
/*
Author: Nguyen Chi Thanh - High School for the Gifted - VNU.HCM (i2528)
*/
#include <bits/stdc++.h>
using namespace std;

/* START OF TEMPALTE */

// #define int long long
#define ll long long
#define ull unsigned long long
#define ld long double
#define pii pair<int, int>
#define pll pair<ll, ll>
#define fi first
#define se second
#define popcount __builtin_popcountll
#define all(x) (x).begin(), (x).end()
#define BIT(x, i) (((x) >> (i)) & 1)
#define MASK(x) (1ll << (x))
#define SZ(a) ((int32_t)a.size())

#define debug(a, l, r) {for (int _i = (l); _i <= (r); ++_i) cout << (a)[_i] << ' '; cout << '\n';}

template<class X, class Y>
bool minimize(X &x, const Y &y) {
    if (x > y) {
        x = y;
        return true;
    } else return false;
}

template<class X, class Y>
bool maximize(X &x, const Y &y) {
    if (x < y) {
        x = y;
        return true;
    } else return false;
}

/* END OF TEMPALTE */

struct DSU {
    int n;
    vector<int> par, sz;

    DSU(int _n) : n(_n), par(n + 5), sz(n + 5, 1) {
        iota(all(par), 0);
    }

    int findSet(int x) {
        while (x != par[x])
            x = par[x] = par[par[x]];
        return x;
    }
 
    bool unite(int x, int y) {
        x = findSet(x); y = findSet(y);
        if (x == y) return 0;
        if (sz[x] < sz[y]) swap(x, y);
 
        sz[x] += sz[y];
        par[y] = x;
 
        return 1;
    }
 
    int size(int u) {
        return sz[findSet(u)];
    }
 
    bool same(int u, int v) {
        return findSet(u) == findSet(v);
    }
};

const int MAXN = 1005;
const int ITER = 60;
int n;
pii points[MAXN];

void init() {
    cin >> n;
    for (int i = 1; i <= n; ++i) {
        int x, y; cin >> x >> y;
        points[i] = {x, y};
    }
}

bool check(ld x) {
    DSU dsu(n);

    for (int i = 1; i <= n; ++i) {
        for (int j = i + 1; j <= n; ++j) {
            ld dist = sqrtl(1ll * (points[i].fi - points[j].fi) * (points[i].fi - points[j].fi)
            + 1ll * (points[i].se - points[j].se) * (points[i].se - points[j].se));
            if (dist <= 2 * x) dsu.unite(i, j);
        }
    }

    for (int i = 2; i <= n; ++i)
        if (!dsu.same(1, i)) return 0;
    return 1;
}

void solve() {
    ld l = 0.0, r = (ld)1e9;
    int iter = 0;
    while (iter < ITER) {
        ld mid = (l + r) / 2.0;
        if (check(mid)) r = mid;
        else l = mid;

        ++iter;
    }

    cout << fixed << setprecision(16);
    cout << l;
}

signed main() {
    #ifdef NCTHANH
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    #endif
    ios_base::sync_with_stdio(0);
    cin.tie(nullptr); cout.tie(nullptr);

    init();
    solve();

    return 0;
}
#Verdict Execution timeMemoryGrader output
Fetching results...