Problem p00362 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int)n; i++)
#define all(c) (c).begin(), (c).end()
#define pb push_back
#define dbg(...)                                                               \\
  do {                                                                         \\
    cerr << __LINE__ << ": ";                                                  \\
    dbgprint(#__VA_ARGS__, __VA_ARGS__);                                       \\
  } while (0);

using namespace std;

namespace std {
template <class S, class T> struct hash<pair<S, T>> {
  size_t operator()(const pair<S, T> &p) const {
    return ((size_t)1e9 + 7) * hash<S>()(p.first) + hash<T>()(p.second);
  }
};
template <class T> struct hash<vector<T>> {
  size_t operator()(const vector<T> &v) const {
    size_t h = 0;
    for (auto i : v)
      h = h * ((size_t)1e9 + 7) + hash<T>()(i) + 1;
    return h;
  }
};
} // namespace std
template <class T> ostream &operator<<(ostream &os, const vector<T> &v) {
  os << "[ ";
  rep(i, v.size()) os << v[i] << (i == v.size() - 1 ? " ]" : ", ");
  return os;
}
template <class T> ostream &operator<<(ostream &os, const set<T> &v) {
  os << "{ ";
  for (const auto &i : v)
    os << i << ", ";
  return os << "}";
}
template <class T, class U>
ostream &operator<<(ostream &os, const map<T, U> &v) {
  os << "{";
  for (const auto &i : v)
    os << " " << i.first << ": " << i.second << ",";
  return os << "}";
}
template <class T, class U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
  return os << "(" << p.first << ", " << p.second << ")";
}
void dbgprint(const string &fmt) { cerr << endl; }
template <class H, class... T>
void dbgprint(const string &fmt, const H &h, const T &...r) {
  cerr << fmt.substr(0, fmt.find(",")) << "= " << h << " ";
  dbgprint(fmt.substr(fmt.find(",") + 1), r...);
}
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pi;
const int inf = (int)1e9;
const double INF = 1e12, EPS = 1e-9;
const int MX = 100000;
const int MX_L = 17;

int n, K;
int parent[MX_L][MX];
int depth[MX];
vector<vector<pi>> e;

void dfs(int c, int p, int d) {
  depth[c] = d;
  parent[0][c] = p;
  for (pi i : e[c]) {
    int to = i.first;
    if (to == p)
      continue;
    dfs(to, c, d + 1);
  }
}
inline int lca(int a, int b) {
  if (depth[a] > depth[b])
    swap(a, b);
  int d = depth[b] - depth[a];
  rep(i, MX_L) if (d & 1 << i) b = parent[i][b];
  if (a == b)
    return a;
  for (int i = MX_L - 1; i >= 0; i--)
    if (parent[i][a] != parent[i][b]) {
      a = parent[i][a];
      b = parent[i][b];
    }
  return parent[0][a];
}

vector<pi> tmpq; // pos, add
ll cost_sum[MX], edge_sum[MX], added[MX];
void build() {
  for (pi i : tmpq)
    added[i.first] += i.second;
  tmpq.clear();
  function<void(int, int, ll, ll)> rec = [&](int c, int p, ll cs, ll es) {
    cost_sum[c] = cs;
    edge_sum[c] = es;
    for (pi i : e[c])
      if (i.first != p) {
        ll ec = added[c] + added[i.first] + i.second;
        ll x = cs + (ec % K ? ec : 0);
        ll y = es + ec;
        rec(i.first, c, x, y);
      }
  };
  rec(0, 0, 0, 0);
}
ll cost(int a, int b) { return cost_sum[a] - cost_sum[b]; }
ll cost(int a, int b, unordered_map<int, int> &m) {
  ll ec = edge_sum[a] - edge_sum[b];
  if (m.count(a))
    ec += m[a];
  if (m.count(b))
    ec += m[b];
  return ec % K ? ec : 0;
}
ll calc(int s, int t) {
  if (s == t)
    return 0;
  ll ans = cost_sum[s] - cost_sum[t];
  unordered_map<int, int> tmpadd;
  unordered_set<pi> es;
  for (pi i : tmpq)
    if (lca(s, i.first) == i.first && lca(i.first, t) == t)
      tmpadd[i.first] += i.second;
  for (pi i : tmpadd) {
    int prev = s, next = parent[0][i.first],
        diff = max(0, depth[s] - depth[i.first] - 1);
    rep(j, MX_L) if (diff >> j & 1) prev = parent[j][prev];
    if (i.first != s)
      es.emplace(prev, i.first);
    if (i.first != t)
      es.emplace(i.first, next);
  }
  for (pi i : es)
    ans -= cost(i.first, i.second) - cost(i.first, i.second, tmpadd);
  return ans;
}
ll query(int s, int t) {
  int m = lca(s, t);
  return calc(s, m) + calc(t, m);
}
int main() {
  cin.tie(0);
  cin.sync_with_stdio(0);
  cin >> n >> K;
  e.resize(n);
  rep(i, n - 1) {
    int a, b, c;
    cin >> a >> b >> c;
    e[a].emplace_back(b, c);
    e[b].emplace_back(a, c);
  }
  dfs(0, 0, 0);
  rep(i, MX_L - 1) rep(j, n) parent[i + 1][j] = parent[i][parent[i][j]];
  build();

  int Q;
  cin >> Q;
  const int B = 300;
  rep(i, Q) {
    string s;
    int a, b;
    cin >> s >> a >> b;
    if (s[0] == 'a') {
      tmpq.emplace_back(a, b);
      if (tmpq.size() == B)
        build();
    } else
      cout << query(a, b) << endl;
  }

  return 0;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int)n; i++)
#define all(c) (c).begin(), (c).end()
#define pb push_back
#define dbg(...)                                                               \\
  do {                                                                         \\
    cerr << __LINE__ << ": ";                                                  \\
    dbgprint(#__VA_ARGS__, __VA_ARGS__);                                       \\
  } while (0);

using namespace std;

namespace std {
template <class S, class T> struct hash<pair<S, T>> {
  size_t operator()(const pair<S, T> &p) const {
    return ((size_t)1e9 + 7) * hash<S>()(p.first) + hash<T>()(p.second);
  }
};
template <class T> struct hash<vector<T>> {
  size_t operator()(const vector<T> &v) const {
    size_t h = 0;
    for (auto i : v)
      h = h * ((size_t)1e9 + 7) + hash<T>()(i) + 1;
    return h;
  }
};
} // namespace std
template <class T> ostream &operator<<(ostream &os, const vector<T> &v) {
  os << "[ ";
  rep(i, v.size()) os << v[i] << (i == v.size() - 1 ? " ]" : ", ");
  return os;
}
template <class T> ostream &operator<<(ostream &os, const set<T> &v) {
  os << "{ ";
  for (const auto &i : v)
    os << i << ", ";
  return os << "}";
}
template <class T, class U>
ostream &operator<<(ostream &os, const map<T, U> &v) {
  os << "{";
  for (const auto &i : v)
    os << " " << i.first << ": " << i.second << ",";
  return os << "}";
}
template <class T, class U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
  return os << "(" << p.first << ", " << p.second << ")";
}
void dbgprint(const string &fmt) { cerr << endl; }
template <class H, class... T>
void dbgprint(const string &fmt, const H &h, const T &...r) {
  cerr << fmt.substr(0, fmt.find(",")) << "= " << h << " ";
  dbgprint(fmt.substr(fmt.find(",") + 1), r...);
}
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pi;
const int inf = (int)1e9;
const double INF = 1e12, EPS = 1e-9;
const int MX = 100000;
const int MX_L = 17;

int n, K;
int parent[MX_L][MX];
int depth[MX];
vector<vector<pi>> e;

void dfs(int c, int p, int d) {
  depth[c] = d;
  parent[0][c] = p;
  for (pi i : e[c]) {
    int to = i.first;
    if (to == p)
      continue;
    dfs(to, c, d + 1);
  }
}
inline int lca(int a, int b) {
  if (depth[a] > depth[b])
    swap(a, b);
  int d = depth[b] - depth[a];
  rep(i, MX_L) if (d & 1 << i) b = parent[i][b];
  if (a == b)
    return a;
  for (int i = MX_L - 1; i >= 0; i--)
    if (parent[i][a] != parent[i][b]) {
      a = parent[i][a];
      b = parent[i][b];
    }
  return parent[0][a];
}

vector<pi> tmpq; // pos, add
ll cost_sum[MX], edge_sum[MX], added[MX];
void build() {
  for (pi i : tmpq)
    added[i.first] += i.second;
  tmpq.clear();
  function<void(int, int, ll, ll)> rec = [&](int c, int p, ll cs, ll es) {
    cost_sum[c] = cs;
    edge_sum[c] = es;
    for (pi i : e[c])
      if (i.first != p) {
        ll ec = added[c] + added[i.first] + i.second;
        ll x = cs + (ec % K ? ec : 0);
        ll y = es + ec;
        rec(i.first, c, x, y);
      }
  };
  rec(0, 0, 0, 0);
}
ll cost(int a, int b) { return cost_sum[a] - cost_sum[b]; }
ll cost(int a, int b, unordered_map<int, int> &m) {
  ll ec = edge_sum[a] - edge_sum[b];
  if (m.count(a))
    ec += m[a];
  if (m.count(b))
    ec += m[b];
  return ec % K ? ec : 0;
}
ll calc(int s, int t) {
  if (s == t)
    return 0;
  ll ans = cost_sum[s] - cost_sum[t];
  unordered_map<int, int> tmpadd;
  for (pi i : tmpq)
    if (lca(s, i.first) == i.first)
      tmpadd[i.first] += i.second;
  for (pi i : tmpadd) {
    int prev = s, next = parent[0][i.first],
        diff = max(0, depth[s] - depth[i.first] - 1);
    rep(j, MX_L) if (diff >> j & 1) prev = parent[j][prev];
    if (i.first != s)
      ans -= cost(prev, i.first) - cost(prev, i.first, tmpadd);
    if (i.first != t)
      ans -= cost(i.first, next) - cost(i.first, next, tmpadd);
  }
  return ans;
}
int query(int s, int t) {
  int m = lca(s, t);
  return calc(s, m) + calc(t, m);
}
int main() {
  cin.tie(0);
  cin.sync_with_stdio(0);
  cin >> n >> K;
  e.resize(n);
  rep(i, n - 1) {
    int a, b, c;
    cin >> a >> b >> c;
    e[a].emplace_back(b, c);
    e[b].emplace_back(a, c);
  }
  dfs(0, 0, 0);
  rep(i, MX_L - 1) rep(j, n) parent[i + 1][j] = parent[i][parent[i][j]];
  build();

  int Q;
  cin >> Q;
  const int B = 1;
  rep(i, Q) {
    string s;
    int a, b;
    cin >> s >> a >> b;
    if (s[0] == 'a') {
      tmpq.emplace_back(a, b);
      if (tmpq.size() == B)
        build();
    } else
      cout << query(a, b) << endl;
  }

  return 0;
}