Submission #792732

#	Time	Username	Problem	Language	Result	Execution time	Memory
792732		arush_agu	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	292 ms	24924 KiB

commuter_pass

#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 ll INF = 4e18;
const ld EPS = 1e-9;

void solve() {
  ll n, m;
  cin >> n >> m;
  ll s, t, u, v;
  cin >> s >> t >> u >> v;
  s--, t--, u--, v--;

  vvll adj(n);
  for (ll i = 0; i < m; i++) {
    ll a, b, c;
    cin >> a >> b >> c;
    a--, b--;
    adj[a].push_back({b, c});
    adj[b].push_back({a, c});
  }

  vl s_dist(n, INF), t_dist(n, INF), u_dist(n, INF), v_dist(n, INF);
  auto f = [&](ll st, vl &dist) -> vl {
    vl order;

    vb vis(n);
    dist[st] = 0;
    priority_queue<llll, vll, greater<llll>> pq;
    pq.push({0, st});

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

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

      order.push_back(u);

      for (auto [v, w] : adj[u])
        if (dist[v] > du + w) {
          dist[v] = du + w;
          pq.push({dist[v], v});
        }
    }
    return order;
  };

  f(u, u_dist), f(v, v_dist), f(t, t_dist);
  vl order = f(s, s_dist);
  reverse(all(order));

  ll ans = u_dist[v];
  for (ll x : order) {
    ans = min(ans, u_dist[x] + v_dist[x]);
    for (auto [y, w] : adj[x])
      if (s_dist[x] + w + t_dist[y] == s_dist[t])
        ans = min({ans, u_dist[x] + v_dist[y], u_dist[y] + v_dist[x]});

    for (auto [y, w] : adj[x])
      if (s_dist[x] + w + t_dist[y] == s_dist[t])
        u_dist[x] = min(u_dist[y], u_dist[x]),
        v_dist[x] = min(v_dist[y], v_dist[x]);
  }

  cout << ans << "\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)

commuter_pass.cpp: In function 'int main()':
commuter_pass.cpp:160:11: warning: unused variable 'start' [-Wunused-variable]
  160 |   clock_t start = clock();
      |           ^~~~~

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 24 / 24
• Subtask 4: 45 / 45