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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#726510#3858. Systematic salesmanahsoltanWA 2ms10076kbC++203.6kb2024-11-09 01:54:452024-11-09 01:54:46

Judging History

你现在查看的是最新测评结果

  • [2024-11-09 01:54:46]
  • 评测
  • 测评结果:WA
  • 用时:2ms
  • 内存:10076kb
  • [2024-11-09 01:54:45]
  • 提交

answer

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

#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())
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;

#ifdef LOCAL
auto operator<<(auto& o, auto x) -> decltype(x.first, o);
auto operator<<(auto& o, auto x) -> decltype(x.end(), o) {
  o << "{";
  for (int i = 0; auto y : x) o << ", " + !i++ * 2 << y;
  return o << "}"; }
auto operator<<(auto& o, auto x) -> decltype(x.first, o) {
  return o << "(" << x.first << ", " << x.second << ")"; }
void __print(auto... x) { ((cerr << x << " "), ...) << endl; }
#define debug(x...) __print("[" #x "]:", x)
#else
#define debug(...) 2137
#endif

template <class T> int sgn(T x) { return (x > 0) - (x < 0); }
template<class T>
struct Point {
  typedef Point P;
  T x, y;
  auto operator<=>(const P&) const = default;
  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 << ")"; }
};
using P = Point<ll>;

bool chmin(double& x, double y) { return y < x ? x = y, 1 : 0; }

const int N = 1010;
int n;
P p[N];
double dp[N][N], f[N][N];
int s[N][N], sf[N][N];

vector<pii> rec(vi v, int d) {
  int m = sz(v);
  if (m == 1) {
    int i = v[0];
    dp[i][i] = 0;
    s[i][i] = sf[i][i] = i;
    return {{i, i}};
  }
  nth_element(v.begin(), (m + 1) / 2 + all(v), [&](int x, int y) {
    if (d % 2 == 0) return p[x].x < p[y].x;
    else return p[x].y < p[y].y;
  });
  vi l(v.begin(), v.begin() + m / 2), r(m / 2 + all(v));
  auto lw = rec(l, d + 1); auto pr = rec(r, d + 1);
  for (auto [i, j] : lw) for (int k : r) {
    if (chmin(f[i][k], dp[i][j] + (p[k] - p[j]).dist())) {
      sf[i][k] = j;
    }
  }
  for (int i : l) for (auto [j, k] : pr) {
    if (chmin(dp[i][k], f[i][j] + dp[j][k])) {
      s[i][k] = j;
    }
  }
  for (auto [i, j] : pr) for (int k : l) {
    if (chmin(f[i][k], dp[i][j] + (p[k] - p[j]).dist())) {
      sf[i][k] = j;
    }
  }
  for (int i : r) for (auto [j, k] : lw) {
    if (chmin(dp[i][k], f[i][j] + dp[j][k])) {
      s[i][k] = j;
    }
  }
  vector<pii> x;
  x.reserve(2 * sz(l) * sz(r));
  for (int i : l) for (int j : r) {
    x.push_back({i, j});
    x.push_back({j, i});
  }
  return x;
}

vi ans;
void buduj(int a, int b) {
  if (a == b) {
    ans.push_back(a);
    return;
  }
  int y = s[a][b];
  int x = sf[a][y];
  buduj(a, x);
  buduj(y, b);
}

int main() {
  cin.tie(0)->sync_with_stdio(0);
  cin >> n;
  rep(i, 0, n) cin >> p[i].x >> p[i].y;
  vi v(n); iota(all(v), 0);
  rep(i, 0, n) rep(j, 0, n) f[i][j] = dp[i][j] = 1 / .0;
  auto pr = rec(v, 0);
  pair<double, pii> bst = {1 / .0, {}};
  for (auto [i, j] : pr) bst = min(bst, {dp[i][j], {i, j}});
  buduj(bst.second.first, bst.second.second);
  cout << fixed << setprecision(12) << bst.first << '\n';
  rep(i, 0, n) cout << ans[i] + 1 << " \n"[i == n - 1];
}

Details

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Test #1:

score: 100
Accepted
time: 0ms
memory: 10076kb

input:

8
7 3
2 0
4 5
1 4
8 2
9 9
0 8
6 1

output:

26.383325771613
6 1 5 8 2 4 3 7

result:

ok correct!

Test #2:

score: -100
Wrong Answer
time: 2ms
memory: 10068kb

input:

20
4 71
52 7
49 15
59 83
12 9
46 6
74 44
89 50
32 10
82 58
11 33
78 72
27 49
64 75
97 0
38 46
91 54
8 70
18 61
79 92

output:

468.909811900288
16 13 18 1 19 11 9 5 3 6 2 8 15 7 17 10 20 14 4 12

result:

wrong answer The first line of your output is 468.909812, but the length of jury's solution is 374.883681