Submission #335765

#	Time	Username	Problem	Language	Result	Execution time	Memory
335765		VROOM_VARUN	Cities (BOI16_cities)	C++14	0 / 100	3399 ms	76860 KiB

cities

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

#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)1e15
#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, k, m;
VVI dp;
VVI dp1;
vector<VII> adj;
VI which;
VVI pws;
vector<bool> vis;

// we can get submasks by doing base 3...

void init() {
  dp.resize(1 << k);
  trav(x, dp) x.assign(n, INF);
  adj.resize(n);
  which.assign(n, -1);
  pws.resize(1 << k);
}

void dijk(int type) {
  // if we want to come from a neighbor
  priority_queue<PII, VII, greater<PII>> pq;

  for (int i = 0; i < n; i++) {
    pq.push(MP(dp[type][i], i));
  }

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

void dfs(int ind, int type) {
  if (vis[ind]) return;
  vis[ind] = true;
  for (auto& x : pws[type]) {
    dp[type][ind] = min(dp[type][ind], dp[x][ind] + dp[type ^ x][ind]);
  }
  for (auto& x : adj[ind]) {
    dfs(x.x, type);
  }
}

void gen() {
  int pw = 1;
  for (int i = 0; i < k; i++) pw *= 3;
  for (int i = 0; i < pw; i++) {
    VI vals(k, 0);
    int ind = 0;
    int cop = i;
    while (cop) {
      vals[ind++] = cop % k;
      cop /= k;
    }
    int val1 = 0;
    int val2 = 0;
    for (int i = 0; i < k; i++) {
      if (vals[i] >= 1) val1 |= (1 << i);
      if (vals[i] == 2) val2 |= (1 << i);
      pws[val1].PB(val2);
    }
  }
}

void process(int type) {
  vis.assign(n, false);
  dfs(0, type);
  vis.assign(n, false);
  dijk(type);
}

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

  cin >> n >> k >> m;

  init();

  for (int i = 0; i < k; i++) {
    int u;
    cin >> u;
    u--;
    which[u] = i;
  }

  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));
  }

  for (int i = 0; i < n; i++) {
    dp[0][i] = 0;
  }

  for (int i = 0; i < n; i++) {
    if (~which[i]) dp[1 << which[i]][i] = 0;
  }

  dp1 = dp;

  gen();

  for (int i = 1; i < (1 << k); i++) process(i);

  cout << *min_element(all(dp[(1 << k) - 1])) << '\n';

  trav(x, dp) debug(x);

  return 0;
}

Compilation message (stderr)

cities.cpp: In function 'int32_t main()':
cities.cpp:19:20: warning: statement has no effect [-Wunused-value]
   19 | #define debug(...) 42
      |                    ^~
cities.cpp:181:15: note: in expansion of macro 'debug'
  181 |   trav(x, dp) debug(x);
      |               ^~~~~
cities.cpp:33:11: warning: unused variable 'first' [-Wunused-variable]
   33 | #define x first
      |           ^~~~~
cities.cpp:50:31: note: in definition of macro 'trav'
   50 | #define trav(a, x) for (auto& a : x)
      |                               ^
cities.cpp:181:8: note: in expansion of macro 'x'
  181 |   trav(x, dp) debug(x);
      |        ^

• Subtask 1: 0 / 22
• Subtask 2: 0 / 14
• Subtask 3: 0 / 15
• Subtask 4: 0 / 23
• Subtask 5: 0 / 26