Submission #8808076

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using VI = vector<int>;
using VL = vector<ll>;
#define FOR(i,a,n) for(int (i)=(a);(i)<(n);++(i))
#define eFOR(i,a,n) for(int (i)=(a);(i)<=(n);++(i))
#define rFOR(i,a,n) for(int (i)=(n)-1;(i)>=(a);--(i))
#define erFOR(i,a,n) for(int (i)=(n);(i)>=(a);--(i))
#define SORT(i) sort((i).begin(),(i).end())
#define rSORT(i,a) sort((i).begin(),(i).end(),(a))
#define all(i) (i).begin(),(i).end()
#define out(y,x) ((y) < 0 || h <= (y) || (x) < 0 || w <= (x))
#define line cout << "------------------------\n" 
#define ENDL(i,n) ((i) == (n) - 1 ? "\n" : " ")
#define stop system("pause")
constexpr ll INF = 1000000000;
constexpr ll LLINF = 1LL << 60;
constexpr ll mod = 1000000007;
constexpr ll MOD = 998244353;
const long double pi = acos(-1);
const long double eps = 1e-10;
template<class T>inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; }return 0; }
template<class T>inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; }return 0; }
inline void init() { cin.tie(nullptr); cout.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); }
template<class T>inline istream& operator>>(istream& is, vector<T>& v) { for (auto& elemnt : v)is >> elemnt; return is; }
template<class T, class U>inline istream& operator>>(istream& is, pair<T, U>& p) { is >> p.first >> p.second; return is; }
template<class T>inline vector<T> vec(size_t a) { return vector<T>(a); }
template<class T>inline vector<T> defvec(T def, size_t a) { return vector<T>(a, def); }
template<class T, class... Ts>inline auto vec(size_t a, Ts... ts) { return vector<decltype(vec<T>(ts...))>(a, vec<T>(ts...)); }
template<class T, class... Ts>inline auto defvec(T def, size_t a, Ts... ts) { return vector<decltype(defvec<T>(def, ts...))>(a, defvec<T>(def, ts...)); }

using P = pair<double, int>;
int main() {
    init();

    double sx, sy, tx, ty; cin >> sx >> sy >> tx >> ty;
    int n; cin >> n;
    n += 2;
    vector<double> x(n), y(n), r(n);
    x[0] = sx, y[0] = sy;
    x[n - 1] = tx, y[n - 1] = ty;
    FOR(i, 1, n - 1)cin >> x[i] >> y[i] >> r[i];

    vector<vector<P>> g(n);
    FOR(i, 0, n)FOR(j, i + 1, n) {
        double dx = x[i] - x[j], dy = y[i] - y[j];
        double cost = sqrt(dx * dx + dy * dy);
        cost = max(cost - r[i] - r[j], 0.0);
        g[i].emplace_back(cost, j);
        g[j].emplace_back(cost, i);
    }

    vector<double> dis(n, LLINF);
    priority_queue<P, vector<P>, greater<P>> dik;
    dis[0] = 0.0;
    dik.emplace(0.0, 0);
    while (!dik.empty()) {
        double d; int now;
        tie(d, now) = dik.top(); dik.pop();
        if (dis[now] < d)continue;
        for (P next : g[now]) {
            double cost; int to;
            tie(cost, to) = next;
            if (!chmin(dis[to], dis[now] + cost))continue;
            dik.emplace(dis[to], to);
        }
    }

    cout << dis[n - 1] << "\n";
}

Submission Info

Judge Result