Keke's delivery service

#include <bits/stdc++.h>
#include <iomanip>
#include <vector>
using namespace std;

#define int long long
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef long double ld;

string to_string(string s) {
    return '"' + s + '"';
}
 
string to_string(const char* s) {
    return to_string((string) s);
}
 
string to_string(bool b) {
    return (b ? "true" : "false");
}
 
template <typename A, typename B>
string to_string(pair<A, B> p) {
    return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
 
template <typename A>
string to_string(A v) {
    bool first = true;
    string res = "{";
    for (const auto &x : v) {
        if (!first) {
            res += ", ";
        }
        first = false;
        res += to_string(x);
    }
    res += "}";
    return res;
}
 
void debug_out() {
    cerr << endl;
}
 
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << " " << to_string(H);
    debug_out(T...);
}
 
#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

/**
 * Author: Ulf Lundstrom
 * Date: 2009-02-26
 * License: CC0
 * Source: My head with inspiration from tinyKACTL
 * Description: Class to handle points in the plane.
 *     T can be e.g. double or long long. (Avoid int.)
 * Status: Works fine, used a lot
 */

template <class T> int sgn(T x) { return (x > 0) - (x < 0); }
template<class T>
struct Point {
    typedef Point P;
    T x, y;
    explicit Point(T x=0, T y=0) : x(x), y(y) {}
    bool operator<(P p) const { return tie(x,y) < tie(p.x,p.y); }
    bool operator==(P p) const { return tie(x,y)==tie(p.x,p.y); }
    P operator+(P p) const { return P(x+p.x, y+p.y); }
    P operator-(P p) const { return P(x-p.x, y-p.y); }
    P operator*(T d) const { return P(x*d, y*d); }
    P operator/(T d) const { return P(x/d, y/d); }
    T dot(P p) const { return x*p.x + y*p.y; }
    T cross(P p) const { return x*p.y - y*p.x; }
    T cross(P a, P b) const { return (a-*this).cross(b-*this); }
    T dist2() const { return x*x + y*y; }
    double dist() const { return sqrt((double)dist2()); }
    // angle to x-axis in interval [-pi, pi]
    double angle() const { return atan2(y, x); }
    P unit() const { return *this/dist(); } // makes dist()=1
    P perp() const { return P(-y, x); } // rotates +90 degrees
    P normal() const { return perp().unit(); }
    // returns point rotated 'a' radians ccw around the origin
    P rotate(double a) const {
        return P(x*cos(a)-y*sin(a),x*sin(a)+y*cos(a)); }
    friend ostream& operator<<(ostream& os, P p) {
        return os << "(" << p.x << "," << p.y << ")"; }
};

const int N = 10;

int n;
Point<int> a[N], b[N];
ld dp[1 << N][1 << N][2 * N];
const ld INF = 1e30;

signed main() {
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit); // RTE if input wrong datatype

    int n;
    cin >> n;

    for (int i = 0; i < n; i++) {
        cin >> a[i].x >> a[i].y;
        cin >> b[i].x >> b[i].y;
    }

    for (int j = 0; j < (1 << N); j++) {
        for (int jj = 0; jj < (1 << N); jj++) {
            for (int i = 0; i < 2*N; i++) {
                dp[j][jj][i] = INF;
            }
        }
    }

    Point<int> origin = Point(0LL, 0LL);

    // start at any begin is dist from that to start
    for (int i = 0; i < n; i++) {
        dp[1 << i][0][i] = (a[i] - origin).dist();
    }

    ld ans = INF;

    for (int amsk = 0; amsk < (1 << n); amsk++) {
        vector<int> nxt;
        for (int bmsk = amsk; ; bmsk = (bmsk - 1) & amsk) {
            nxt.push_back(bmsk);
            if (bmsk == 0) break;
        }
        reverse(all(nxt));
        for (int bmsk : nxt) {
            for (int pos = 0; pos < 2 * n; pos++) {
                if (pos >= n) { // end
                    int i = pos - n;
                    if (!(bmsk >> i & 1)) continue;

                    int nbmsk = bmsk ^ (1 << i);
                    // go from another start
                    for (int j = 0; j < n; j++) {
                        if (amsk >> j & 1) {
                            dp[amsk][bmsk][pos] = min(dp[amsk][bmsk][pos], dp[amsk][nbmsk][j] + (b[i] - a[j]).dist());
                        }   
                    }

                    // go from another end
                    for (int j = 0; j < n; j++) {
                        if (nbmsk >> j & 1) {
                            dp[amsk][bmsk][pos] = min(dp[amsk][bmsk][pos], dp[amsk][nbmsk][j+n] + (b[i] - b[j]).dist());
                        }   
                    }
                } else { // start
                    int i = pos;
                    if (!(amsk >> i & 1)) continue;
                    
                    int namsk = amsk ^ (1 << i);
                    // go from another start
                    for (int j = 0; j < n; j++) {
                        if (namsk >> j & 1) {
                            dp[amsk][bmsk][i] = min(dp[amsk][bmsk][i], dp[namsk][bmsk][j] + (a[j] - a[i]).dist());
                        }
                    }

                    // go from another end
                    for (int j = 0; j < n; j++) {
                        if (bmsk >> j & 1) {
                            dp[amsk][bmsk][i] = min(dp[amsk][bmsk][i], dp[namsk][bmsk][j+n] + (b[j] - a[i]).dist());
                        }
                    }
                }

                // debug(bitset<N>(amsk).to_string(), bitset<N>(bmsk).to_string(), pos, dp[amsk][bmsk][pos]);
            }
        }
    }

    for (int i = n; i < 2*n; i++) {
        ans = min(ans, dp[(1<<n)-1][(1<<n)-1][i] + (b[i-n] - origin).dist());
    }

    cout << fixed << setprecision(10) << ans;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

Test 27

Verdict: ACCEPTED

Test 28

Verdict: ACCEPTED

Test 29

Verdict: ACCEPTED

Test 30

Verdict: ACCEPTED

Test 31

Verdict: ACCEPTED

Test 32

Verdict: ACCEPTED

Test 33

Verdict: ACCEPTED

Test 34

Verdict: ACCEPTED

Test 35

Verdict: ACCEPTED

Test 36

Verdict: ACCEPTED

Test 37

Verdict: ACCEPTED

Test 38

Verdict: ACCEPTED

Test 39

Verdict: ACCEPTED

Test 40

Verdict: ACCEPTED

Test 41

Verdict: ACCEPTED

Test 42

Verdict: ACCEPTED

Test 43

Verdict: ACCEPTED

Test 44

Verdict: ACCEPTED

Test 45

Verdict: ACCEPTED

Test 46

Verdict: ACCEPTED

Test 47

Verdict: ACCEPTED

Test 48

Verdict: ACCEPTED

Test 49

Verdict: ACCEPTED

Test 50

Verdict: ACCEPTED

Test 51

Verdict: ACCEPTED

Test 52

Verdict: ACCEPTED

Test 53

Verdict: ACCEPTED

Test 54

Verdict: ACCEPTED

Test 55

Verdict: ACCEPTED

Test 56

Verdict: ACCEPTED

Test 57

Verdict: ACCEPTED

Test 58

Verdict: ACCEPTED

Test 59

Verdict: ACCEPTED

Test 60

Verdict: ACCEPTED

Test 61

Verdict: ACCEPTED

Test 62

Verdict: ACCEPTED