Submission #804102

#	Time	Username	Problem	Language	Result	Execution time	Memory
804102		arush_agu	Evacuation plan (IZhO18_plan)	C++17	100 / 100	1238 ms	79472 KiB

plan

#include <algorithm>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#ifdef DEBUG
#include <time.h>
#endif

#define all(a) (a).begin(), (a).end()
#define rev(a) (a).rbegin(), (a).rend()
#define F first
#define S second
int recur_depth = 0;
#ifdef DEBUG
#define dbg(x)                                                                 \
  {                                                                            \
    ++recur_depth;                                                             \
    auto x_ = x;                                                               \
    --recur_depth;                                                             \
    cerr << string(recur_depth, '\t') << "\e[91m" << __func__ << ":"           \
         << __LINE__ << "\t" << #x << " = " << x_ << "\e[39m" << endl;         \
  }
#else
#define dbg(x)
#endif

using namespace std;
using namespace __gnu_pbds;

typedef pair<int, int> ii;

typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> llll;

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pair<int, int>> vii;
typedef vector<vii> vvii;

typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<pair<ll, ll>> vll;
typedef vector<vll> vvll;

typedef vector<bool> vb;

template <class type1>
using ordered_set = tree<type1, null_type, less<type1>, rb_tree_tag,
                         tree_order_statistics_node_update>;

template <typename A, typename B>
ostream &operator<<(ostream &os, const pair<A, B> &p) {
  return os << '(' << p.first << ", " << p.second << ')';
}
template <typename T_container, typename T = typename enable_if<
                                    !is_same<T_container, string>::value,
                                    typename T_container::value_type>::type>
ostream &operator<<(ostream &os, const T_container &v) {
  os << '{';
  string sep;
  for (const T &x : v)
    os << sep << x, sep = ", ";
  return os << '}';
}

const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
const int INF = 1e9;
const ld EPS = 1e-9;

struct DSU {
  int n;
  vi par, sz;

  DSU(int n) : n(n) {
    par = vi(n, -1);
    sz = vi(n, 1);
  }

  int find(int x) {
    if (par[x] == -1)
      return x;
    return par[x] = find(par[x]);
  }

  void merge(int u, int v) {
    u = find(u), v = find(v);
    if (u == v)
      return;
    if (sz[u] < sz[v])
      swap(u, v);
    sz[u] += sz[v];
    par[v] = u;
  }

  bool connected(int u, int v) { return find(u) == find(v); }
};

void solve() {
  int n, m;
  cin >> n >> m;
  vvii adj(n);
  vvi ed(m);
  for (int i = 0; i < m; i++) {
    int u, v, w;
    cin >> u >> v >> w;
    u--, v--;
    adj[u].push_back({v, w}), adj[v].push_back({u, w});
    ed[i] = {u, v, w};
  }

  int k;
  cin >> k;
  vi nuc(k);
  for (int &x : nuc)
    cin >> x, x--;

  vi dist(n, INF);
  vb vis(n);
  priority_queue<ii, vii, greater<ii>> pq;
  for (int &x : nuc)
    pq.push({0, x}), dist[x] = 0;

  while (!pq.empty()) {
    auto [d, u] = pq.top();
    pq.pop();

    if (vis[u])
      continue;
    vis[u] = 1;

    for (auto [v, w] : adj[u])
      if (!vis[v] && dist[v] > w + d) {
        dist[v] = d + w;
        pq.push({d + w, v});
      }
  }
  sort(all(ed), [&](vi a, vi b) {
    return min(dist[a[0]], dist[a[1]]) > min(dist[b[0]], dist[b[1]]);
  });

  vi ed_idx;

  DSU d(n);
  for (int i = 0; i < m; i++) {
    int u = ed[i][0], v = ed[i][1];
    if (d.connected(u, v))
      continue;
    d.merge(u, v);
    ed_idx.push_back(i);
  }

  vvi nadj(n);
  for (int &idx : ed_idx) {
    int u = ed[idx][0], v = ed[idx][1];
    nadj[u].push_back(v);
    nadj[v].push_back(u);
  }

  const int MAXLG = 22;
  vvi par(MAXLG, vi(n, -1));
  vi depth(n);
  function<void(int, int, int)> f = [&](int u, int p, int d) {
    par[0][u] = p;
    depth[u] = d;
    for (int &v : nadj[u])
      if (v != p) {
        f(v, u, d + 1);
      }
  };
  f(0, -1, 0);

  for (int j = 1; j < MAXLG; j++)
    for (int i = 0; i < n; i++)
      if (par[j - 1][i] != -1)
        par[j][i] = par[j - 1][par[j - 1][i]];
  vvi cost(MAXLG, vi(n));
  for (int i = 0; i < n; i++)
    cost[0][i] = min(dist[i], par[0][i] == -1 ? INF : dist[par[0][i]]);
  for (int j = 1; j < MAXLG; j++)
    for (int i = 0; i < n; i++)
      cost[j][i] = min(cost[j - 1][i],
                       par[j - 1][i] == -1 ? INF : cost[j - 1][par[j - 1][i]]);

  auto kth = [&](int u, int k) {
    if (depth[u] < k)
      return -1;

    for (int i = MAXLG - 1; i >= 0; i--)
      if (k & (1 << i))
        u = par[i][u];
    return u;
  };

  auto lca = [&](int u, int v) {
    if (depth[u] < depth[v])
      swap(u, v);
    u = kth(u, depth[u] - depth[v]);
    if (u == v)
      return u;

    for (int i = MAXLG - 1; i >= 0; i--)
      if (par[i][u] != par[i][v]) {
        u = par[i][u];
        v = par[i][v];
      }

    return par[0][u];
  };

  auto ans = [&](int u, int v) {
    int l = lca(u, v);
    int res = INF;

    int k1 = depth[u] - depth[l];
    for (int i = MAXLG - 1; i >= 0; i--)
      if (k1 & (1 << i)) {
        res = min(res, cost[i][u]);
        u = par[i][u];
      }
    int k2 = depth[v] - depth[l];
    for (int i = MAXLG - 1; i >= 0; i--)
      if (k2 & (1 << i)) {
        res = min(res, cost[i][v]);
        v = par[i][v];
      }
    return res;
  };

  int q;
  cin >> q;
  while (q--) {
    int s, t;
    cin >> s >> t;
    s--, t--;

    cout << ans(s, t) << "\n";
  }
}

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);

  clock_t start = clock();

  int test_cases = 1;
  // cin >> test_cases;

  while (test_cases--)
    solve();

#ifdef DEBUG
  cerr << fixed << setprecision(10)
       << "\nTime Taken: " << (double)(clock() - start) / CLOCKS_PER_SEC
       << "s\n";
#endif
  return 0;
}

Compilation message (stderr)

plan.cpp: In function 'int main()':
plan.cpp:266:11: warning: unused variable 'start' [-Wunused-variable]
  266 |   clock_t start = clock();
      |           ^~~~~

• Subtask 1: 10 / 10
• Subtask 2: 13 / 13
• Subtask 3: 12 / 12
• Subtask 4: 19 / 19
• Subtask 5: 46 / 46