Problem p02648 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <algorithm>
#include <iostream>
#include <numeric>
#include <string>
#include <tuple>
#include <utility>
#include <vector>

#define REP(i, a, b) for (int i = int(a); i < int(b); i++)
using namespace std;
using ll = long long int;
using P = pair<int, int>;

// clang-format off
#ifdef _DEBUG_
#define dump(...) do{ cerr << __LINE__ << ":\\t" << #__VA_ARGS__ << " = "; PPPPP(__VA_ARGS__); cerr << endl; } while(false)
template<typename T> void PPPPP(T t) { cerr << t; }
template<typename T, typename... S> void PPPPP(T t, S... s) { cerr << t << ", "; PPPPP(s...); }
#else
#define dump(...) do{ } while(false)
#endif
template<typename T> vector<T> make_v(size_t a, T b) { return vector<T>(a, b); }
template<typename... Ts> auto make_v(size_t a, Ts... ts) { return vector<decltype(make_v(ts...))>(a, make_v(ts...)); }
template<typename T> bool chmin(T &a, T b) { if (a > b) {a = b; return true; } return false; }
template<typename T> bool chmax(T &a, T b) { if (a < b) {a = b; return true; } return false; }
template<typename T> void print(T a) { cout << a << endl; }
template<typename T, typename... Ts> void print(T a, Ts... ts) { cout << a << ' '; print(ts...); }
template<typename T> istream &operator,(istream &in, T &t) { return in >> t; }
// clang-format on

#include <array>
template <size_t N> class INDEX {
  array<size_t, N> arr;

public:
  template <typename... T>
  INDEX(T... _arr) : arr({{static_cast<size_t>(_arr)...}}) {}
  template <typename... T> size_t operator()(T... _arr) {
    size_t position[] = {static_cast<size_t>(_arr)...};
    static_assert(N == size(position));
    size_t res = 0, width = 1;
    for (int i = N - 1; i >= 0; i--) {
      res += width * position[i];
      width *= arr[i];
    }
    return res;
  }
};
template <typename... T> auto Index(T... args) {
  unsigned int arr[] = {static_cast<unsigned int>(args)...};
  constexpr size_t N = size(arr);
  return INDEX<N>(args...);
}
template <typename T, typename... Args> auto make_v_flat(T init, Args... args) {
  return vector<T>((1 * ... * args), init);
}

#include <functional>

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);

  int n;
  cin, n;
  vector<int> v(n), w(n);
  REP(i, 0, n) { cin, v[i], w[i]; }

  const int K = 9, maxL = 100010;
  auto dp = make_v_flat(0, 1 << K, maxL);
  auto index = Index(1 << K, maxL);
  dp[index(0, w[0])] = v[0];
  REP(i, 1, maxL) { chmax(dp[index(0, i)], dp[index(0, i - 1)]); }
  REP(i, 1, 1 << K) {
    if (i >= n)
      continue;
    int prev = (i - 1) / 2;
    REP(j, 0, maxL) {
      chmax(dp[index(i, j)], dp[index(prev, j)]);
      if (j + w[i] < maxL) {
        chmax(dp[index(i, j + w[i])], dp[index(prev, j)] + v[i]);
      }
    }
    REP(j, 1, maxL) { chmax(dp[index(i, j)], dp[index(i, j - 1)]); }
  }

  function<int(int, int)> dfs = [&](int vertex, int weight) {
    if (vertex < (1 << K)) {
      return dp[index(vertex, weight)];
    }
    int parent = (vertex - 1) / 2;
    int res = dfs(parent, weight);
    if (weight >= w[vertex]) {
      chmax(res, dfs(parent, weight - w[vertex]) + v[vertex]);
    }
    return res;
  };

  int q;
  cin, q;
  REP(_, 0, q) {
    int u, L;
    cin, u, L;
    print(dfs(u - 1, L));
  }
  return 0;
}


Error: TLE

Fixed submission:

#include <algorithm>
#include <iostream>
#include <numeric>
#include <string>
#include <tuple>
#include <utility>
#include <vector>

#define REP(i, a, b) for (int i = int(a); i < int(b); i++)
using namespace std;
using ll = long long int;
using P = pair<int, int>;

// clang-format off
#ifdef _DEBUG_
#define dump(...) do{ cerr << __LINE__ << ":\\t" << #__VA_ARGS__ << " = "; PPPPP(__VA_ARGS__); cerr << endl; } while(false)
template<typename T> void PPPPP(T t) { cerr << t; }
template<typename T, typename... S> void PPPPP(T t, S... s) { cerr << t << ", "; PPPPP(s...); }
#else
#define dump(...) do{ } while(false)
#endif
template<typename T> vector<T> make_v(size_t a, T b) { return vector<T>(a, b); }
template<typename... Ts> auto make_v(size_t a, Ts... ts) { return vector<decltype(make_v(ts...))>(a, make_v(ts...)); }
template<typename T> bool chmin(T &a, T b) { if (a > b) {a = b; return true; } return false; }
template<typename T> bool chmax(T &a, T b) { if (a < b) {a = b; return true; } return false; }
template<typename T> void print(T a) { cout << a << endl; }
template<typename T, typename... Ts> void print(T a, Ts... ts) { cout << a << ' '; print(ts...); }
template<typename T> istream &operator,(istream &in, T &t) { return in >> t; }
// clang-format on

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);

  int n;
  cin, n;
  vector<int> v(n), w(n);
  REP(i, 0, n) { cin, v[i], w[i]; }
  int q;
  cin, q;
  REP(_, 0, q) {
    int u, L;
    cin, u, L;
    vector<int> vv, ww;
    while (u) {
      vv.push_back(v[u - 1]);
      ww.push_back(w[u - 1]);
      u /= 2;
    }
    int lsz = vv.size() / 2;
    int rsz = vv.size() - lsz;
    vector<P> m1;
    m1.emplace_back(0, 0);
    REP(i, 0, 1 << lsz) {
      int value = 0, weight = 0;
      REP(j, 0, lsz) {
        if ((i >> j) & 1) {
          value += vv[j];
          weight += ww[j];
        }
      }
      if (weight > L)
        continue;
      m1.emplace_back(weight, value);
    }
    sort(m1.begin(), m1.end());
    int prev = -1;
    for (auto &[key, value] : m1) {
      chmax(value, prev);
      chmax(prev, value);
    }

    int ans = 0;
    REP(i, 0, 1 << rsz) {
      int value = 0, weight = 0;
      REP(j, 0, rsz) {
        if ((i >> j) & 1) {
          value += vv[lsz + j];
          weight += ww[lsz + j];
        }
      }
      if (weight > L)
        continue;
      auto it = lower_bound(m1.begin(), m1.end(), P(L - weight, 1 << 30));
      it--;
      chmax(ans, it->second + value);
    }
    print(ans);
  }
  return 0;
}