Submission #536079

#	Time	Username	Problem	Language	Result	Execution time	Memory
536079		Alex_tz307	Šarenlist (COCI22_sarenlist)	C++17	110 / 110	17 ms	332 KiB

Main

#include <bits/stdc++.h>

using namespace std;

const int mod = 1e9 + 7;
const int kN = 60;
const int kM = 15;
vector<pair<int, int>> g[1 + kN];
map<pair<int, int>, int> indexOfPath;
int64_t edges[kM];
vector<int> G[kM];
bitset<kM> vis;

void addSelf(int &x, int y) {
  x += y;
  if (x >= mod) {
    x -= mod;
  }
}

void multSelf(int &x, const int &y) {
  x = (int64_t)x * y % mod;
}

int Pow(int x, int n) {
  int ans = 1;
  while (n) {
    if (n & 1) {
      multSelf(ans, x);
    }
    multSelf(x, x);
    n >>= 1;
  }
  return ans;
}

void dfs1(int root, int u, int par, int64_t mask) {
  if (indexOfPath.find({root, u}) != indexOfPath.end()) {
    edges[indexOfPath[{root, u}]] = mask;
  }
  for (auto it : g[u]) {
    int v, e;
    tie(v, e) = it;
    if (v != par) {
      dfs1(root, v, u, mask | (1LL << e));
    }
  }
}

void dfs2(int u, int mask) {
  vis[u] = true;
  for (int v : G[u]) {
    if (!vis[v] && (mask & (1 << v))) {
      dfs2(v, mask);
    }
  }
}

void testCase() {
  int n, m, k;
  cin >> n >> m >> k;
  for (int i = 0; i < n - 1; ++i) {
    int u, v;
    cin >> u >> v;
    g[u].emplace_back(v, i);
    g[v].emplace_back(u, i);
  }
  vector<pair<int, int>> paths;
  for (int i = 0; i < m; ++i) {
    int u, v;
    cin >> u >> v;
    if (v < u) {
      swap(u, v);
    }
    if (indexOfPath.find({u, v}) != indexOfPath.end()) {
      i -= 1;
      m -= 1;
      continue;
    }
    paths.emplace_back(u, v);
    indexOfPath[{u, v}] = i;
  }
  for (int v = 1; v <= n; ++v) {
    dfs1(v, v, 0, 0);
  }
  for (int i = 0; i < m - 1; ++i) {
    for (int j = i + 1; j < m; ++j) {
      if (edges[i] & edges[j]) {
        G[i].emplace_back(j);
        G[j].emplace_back(i);
      }
    }
  }
  int ans = 0;
  for (int mask = 0; mask < (1 << m); ++mask) {
    int64_t allEdges = 0;
    int cnt = 0;
    vis.reset();
    for (int i = 0; (1 << i) <= mask; ++i) {
      if (mask & (1 << i)) {
        allEdges |= edges[i];
        if (!vis[i]) {
          cnt += 1;
          dfs2(i, mask);
        }
      }
    }
    cnt += n - 1 - __builtin_popcountll(allEdges);
    if (__builtin_popcount(mask) % 2 == 0) {
      addSelf(ans, Pow(k, cnt));
    } else {
      addSelf(ans, mod - Pow(k, cnt));
    }
  }
  cout << ans << '\n';
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  int tests = 1;
  for (int tc = 0; tc < tests; ++tc) {
    testCase();
  }
  return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 65 / 65