Submission #202432

#	Time	Username	Problem	Language	Result	Execution time	Memory
202432		quocnguyen1012	Paths (BOI18_paths)	C++14	100 / 100	486 ms	59768 KiB

paths

#include <bits/stdc++.h>

#define fi first
#define se second
#define mp make_pair
#define pb push_back

using namespace std;
typedef long long ll;

const int maxn = 3e5 + 5;
const ll llinf = 1e18;

bool testbit(int x, int n)
{
  return x >> n & 1;
}

int addbit(int x, int n)
{
  return x + (1 << n);
}

int delbit(int x, int n)
{
  return x - (1 << n);
}

int f[maxn][1 << 5];
int col[maxn];
vector<int> adj[maxn];
int N, K, M;

int solve(int u, int mask)
{
  int & res = f[u][mask];
  if (res != -1) return res;
  res = 1;
  for (int v : adj[u]){
    if (testbit(mask, col[v]) == 0){
      res += solve(v, addbit(mask, col[v]));
    }
  }
  return res;
}

signed main(void)
{
  ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  if (fopen("A.INP", "r")){
    freopen("A.INP", "r", stdin);
    freopen("A.OUT", "w", stdout);
  }
  cin >> N >> M >> K;
  for (int i = 1; i <= N; ++i){
    cin >> col[i]; --col[i];
  }
  while (M--){
    int u, v; cin >> u >> v;
    adj[u].pb(v); adj[v].pb(u);
  }
  memset(f, -1, sizeof f);
  ll res = 0;
  for (int i = 1; i <= N; ++i){
    res += solve(i, (1 << col[i]));
  }
  cout << res - N;
}

Compilation message (stderr)

paths.cpp: In function 'int main()':
paths.cpp:51:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     freopen("A.INP", "r", stdin);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
paths.cpp:52:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     freopen("A.OUT", "w", stdout);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 23 / 23
• Subtask 2: 20 / 20
• Subtask 3: 27 / 27
• Subtask 4: 30 / 30