Submission #334317

#	Time	Username	Problem	Language	Result	Execution time	Memory
334317		VROOM_VARUN	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	407 ms	28144 KiB

commuter_pass

/*
ID: varunra2
LANG: C++
TASK: pass
*/

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

#ifdef DEBUG
#include "lib/debug.h"
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#define debug_arr(...) \
  cerr << "[" << #__VA_ARGS__ << "]:", debug_arr(__VA_ARGS__)
#pragma GCC diagnostic ignored "-Wsign-compare"
//#pragma GCC diagnostic ignored "-Wunused-parameter"
//#pragma GCC diagnostic ignored "-Wunused-variable"
#else
#define debug(...) 42
#endif

#define int long long

#define EPS 1e-9
#define IN(A, B, C) assert(B <= A && A <= C)
#define INF (int)1e16
#define MEM(a, b) memset(a, (b), sizeof(a))
#define MOD 1000000007
#define MP make_pair
#define PB push_back
#define all(cont) cont.begin(), cont.end()
#define rall(cont) cont.end(), cont.begin()
#define x first
#define y second

const double PI = acos(-1.0);
typedef long long ll;
typedef long double ld;
typedef pair<int, int> PII;
typedef map<int, int> MPII;
typedef multiset<int> MSETI;
typedef set<int> SETI;
typedef set<string> SETS;
typedef vector<int> VI;
typedef vector<PII> VII;
typedef vector<VI> VVI;
typedef vector<string> VS;

#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define trav(a, x) for (auto& a : x)
#define sz(x) (int)(x).size()
typedef pair<int, int> pii;
typedef vector<int> vi;
#pragma GCC diagnostic ignored "-Wsign-compare"
// util functions

int n, m;
int a, b, c, d;
vector<VII> adj;
vector<VII> dadj;  // directed
VII dst;
VI da, db, dc, dd;
vector<bool> vis;
int ret = INF;

void init() {
  adj.resize(n);
  dadj.resize(n);
  dst.resize(n);
  vis.assign(n, false);
}

VI dijk(int src) {
  VI dist(n, INF);
  vector<bool> vis(n, false);
  dist[src] = 0;
  priority_queue<PII, VII, greater<PII>> pq;
  pq.push(MP(0, src));

  while (!pq.empty()) {
    int u = pq.top().y;
    pq.pop();
    if (vis[u]) continue;
    vis[u] = true;
    for (auto& x : adj[u]) {
      if (vis[x.x]) continue;
      if (dist[x.x] > dist[u] + x.y) {
        dist[x.x] = dist[u] + x.y;
        pq.push(MP(dist[x.x], x.x));
      }
    }
  }
  return dist;
}

void dfs(int u) {
  if (vis[u]) return;
  vis[u] = true;
  int val1 = dst[u].x;
  int val2 = dst[u].y;
  for (auto& x : dadj[u]) {
    dfs(x.x);
    dst[u].x = min(dst[u].x, dst[x.x].x);
    dst[u].y = min(dst[u].y, dst[x.x].y);
  }
  ret = min(ret, min(val1 + dst[u].y, val2 + dst[u].x));
}

int longestDAG() {
  for (int i = 0; i < n; i++) {
    dst[i] = MP(dc[i], dd[i]);
  }
  // debug(dst);
  for (int i = 0; i < n; i++) {
    dfs(i);
  }
  // debug(dst);
  return ret;
}

int32_t main() {
  // #ifndef ONLINE_JUDGE
  // freopen("pass.in", "r", stdin);
  // freopen("pass.out", "w", stdout);
  // #endif
  cin.sync_with_stdio(0);
  cin.tie(0);

  cin >> n >> m >> a >> b >> c >> d;

  init();

  for (int i = 0; i < m; i++) {
    int u, v, w;
    cin >> u >> v >> w;
    u--, v--;
    adj[u].PB(MP(v, w));
    adj[v].PB(MP(u, w));
  }

  // trav(x, adj) debug(x);

  a--, b--, c--, d--;

  da = dijk(a), db = dijk(b), dc = dijk(c), dd = dijk(d);

  // debug(da);
  // debug(db);
  // debug(dc);
  // debug(dd);

  int dab = da[b];
  int dcd = dc[d];

  rep(u, 0, n) {
    trav(x, adj[u]) {
      // is (u, v) satisfactory
      int v = x.x;
      int dist = x.y;
      if (dab == da[u] + db[v] + dist) dadj[u].PB(x);
    }
  }

  cout << longestDAG() << '\n';

  return 0;
}

Compilation message (stderr)

commuter_pass.cpp: In function 'int32_t main()':
commuter_pass.cpp:153:7: warning: unused variable 'dcd' [-Wunused-variable]
  153 |   int dcd = dc[d];
      |       ^~~

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