Problem p02350 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
using namespace std;
using lint = long long int;
template <class T = int> using V = vector<T>;
template <class T = int> using VV = V<V<T>>;
template <class T> void assign(V<T> &v, int n, const T &a = T()) {
  v.assign(n, a);
}
template <class T, class... U> void assign(V<T> &v, int n, const U &...u) {
  v.resize(n);
  for (auto &&i : v)
    assign(i, u...);
}

struct M {
  using T = array<lint, 3>; // min, max, sum
  using U = array<lint, 2>; // linear function
  static T op(const T &a, const T &b) {
    return T{min(a[0], b[0]), max(a[1], b[1]), a[2] + b[2]};
  }
  static constexpr T e() {
    return T{numeric_limits<lint>::max(), numeric_limits<lint>::min(), 0};
  }
  static void ap(T &a, const U &g, int k) {
    for (int i = 0; i < 3; i++)
      a[i] = g[0] * a[i] + (i == 2 ? k : 1) * g[1];
    if (g[0] < 0)
      swap(a[0], a[1]);
  }
  static void ap(U &f, const U &g) {
    f[0] *= g[0];
    f[1] = g[0] * f[1] + g[1];
  }
  static constexpr U id() { return U{1, 0}; }
};

template <class M> struct ST {
  using T = typename M::T;
  using U = typename M::U;
  int n, h;
  V<T> t;
  V<U> u;
  V<> k;

  ST(int n) : n(n), h(8 * sizeof(int) - __builtin_clz(max(n - 1, 1))) {
    t.assign(2 * n, M::e());
    u.assign(n, M::id());
    k.assign(2 * n, 1);
    for (int i = n - 1; i; i--)
      k[i] = k[2 * i] + k[2 * i + 1];
  }

  void _ap(int i, const U &f) {
    M::ap(t[i], f, k[i]);
    if (i < n)
      M::ap(u[i], f);
  }

  void build() {
    for (int i = n - 1; i; i--)
      t[i] = M::op(t[2 * i], t[2 * i + 1]);
  }

  T get(int l, int r) {
    set(l, r, M::id());
    T resl = M::e(), resr = M::e();
    for (l += n, r += n; l < r; l >>= 1, r >>= 1) {
      if (l & 1)
        resl = M::op(resl, t[l++]);
      if (r & 1)
        resr = M::op(t[--r], resr);
    }
    return M::op(resl, resr);
  }

  void push() {
    for (int i = 1; i < n; i++) {
      _ap(2 * i, u[i]);
      _ap(2 * i + 1, u[i]);
      u[i] = M::id();
    }
  }

  void set(int l, int r, const U &f) {
    for (int hl = 8 * sizeof(int) - __builtin_clz(l + n) - 1,
             hr = 8 * sizeof(int) - __builtin_clz(r - 1 + n) - 1;
         hr > 0; hl--, hr--) {
      int i = r - 1 + n >> hr;
      _ap(2 * i, u[i]);
      _ap(2 * i + 1, u[i]);
      u[i] = M::id();
      i = l + n >> hl;
      if (i == r - 1 + n >> hr or i >= n)
        continue;
      _ap(2 * i, u[i]);
      _ap(2 * i + 1, u[i]);
      u[i] = M::id();
    }
    // for (int i = h; i; i--) {
    //   int j = (l + n) >> i;
    //   _ap(2 * j, u[j]);
    //   _ap(2 * j + 1, u[j]);
    //   u[j] = M::id();
    //   if (j == (r - 1 + n) >> i) continue;
    //   j = (r - 1 + n) >> i;
    //   _ap(2 * j, u[j]);
    //   _ap(2 * j + 1, u[j]);
    //   u[j] = M::id();
    // }
    for (int i = l + n, j = r + n; i < j; i >>= 1, j >>= 1) {
      if (i & 1)
        _ap(i++, f);
      if (j & 1)
        _ap(--j, f);
    }
    for (l += n; !(l & 1);)
      l >>= 1;
    while (l >>= 1)
      t[l] = M::op(t[2 * l], t[2 * l + 1]);
    for (r += n; !(r & 1);)
      r >>= 1;
    while (r >>= 1)
      t[r] = M::op(t[2 * r], t[2 * r + 1]);
  }
};

int main() {
  cin.tie(NULL);
  ios::sync_with_stdio(false);
  int n, q;
  cin >> n >> q;
  ST<M> st(n);
  for (int i = 0; i < n; i++)
    st.t[i + n].fill(numeric_limits<int>::max());
  st.build();
  for (int i = 0; i < q; i++) {
    int t;
    cin >> t;
    if (t) {
      int l, r;
      cin >> l >> r, r++;
      cout << st.get(l, r)[0] << '\\n';
    } else {
      int l, r, x;
      cin >> l >> r >> x, r++;
      st.set(l, r, M::U{0, x});
    }
  }
}


Error: -6
free(): invalid pointer


Fixed submission:

#include <bits/stdc++.h>
using namespace std;
using lint = long long int;
template <class T = int> using V = vector<T>;
template <class T = int> using VV = V<V<T>>;
template <class T> void assign(V<T> &v, int n, const T &a = T()) {
  v.assign(n, a);
}
template <class T, class... U> void assign(V<T> &v, int n, const U &...u) {
  v.resize(n);
  for (auto &&i : v)
    assign(i, u...);
}

struct M {
  using T = array<lint, 3>; // min, max, sum
  using U = array<lint, 2>; // linear function
  static T op(const T &a, const T &b) {
    return T{min(a[0], b[0]), max(a[1], b[1]), a[2] + b[2]};
  }
  static constexpr T e() {
    return T{numeric_limits<lint>::max(), numeric_limits<lint>::min(), 0};
  }
  static void ap(T &a, const U &g, int k) {
    for (int i = 0; i < 3; i++)
      a[i] = g[0] * a[i] + (i == 2 ? k : 1) * g[1];
    if (g[0] < 0)
      swap(a[0], a[1]);
  }
  static void ap(U &f, const U &g) {
    f[0] *= g[0];
    f[1] = g[0] * f[1] + g[1];
  }
  static constexpr U id() { return U{1, 0}; }
};

template <class M> struct ST {
  using T = typename M::T;
  using U = typename M::U;
  int n, h;
  V<T> t;
  V<U> u;
  V<> k;

  ST(int n) : n(n), h(8 * sizeof(int) - __builtin_clz(max(n - 1, 1))) {
    t.assign(2 * n, M::e());
    u.assign(n, M::id());
    k.assign(2 * n, 1);
    for (int i = n - 1; i; i--)
      k[i] = k[2 * i] + k[2 * i + 1];
  }

  void _ap(int i, const U &f) {
    M::ap(t[i], f, k[i]);
    if (i < n)
      M::ap(u[i], f);
  }

  void build() {
    for (int i = n - 1; i; i--)
      t[i] = M::op(t[2 * i], t[2 * i + 1]);
  }

  T get(int l, int r) {
    set(l, r, M::id());
    T resl = M::e(), resr = M::e();
    for (l += n, r += n; l < r; l >>= 1, r >>= 1) {
      if (l & 1)
        resl = M::op(resl, t[l++]);
      if (r & 1)
        resr = M::op(t[--r], resr);
    }
    return M::op(resl, resr);
  }

  void push() {
    for (int i = 1; i < n; i++) {
      _ap(2 * i, u[i]);
      _ap(2 * i + 1, u[i]);
      u[i] = M::id();
    }
  }

  void set(int l, int r, const U &f) {
    for (int hl = 8 * sizeof(int) - __builtin_clz(l + n) - 1,
             hr = 8 * sizeof(int) - __builtin_clz(r - 1 + n) - 1;
         hl > 0 or hr > 0; hl--, hr--) {
      int i = l + n >> hl;
      _ap(2 * i, u[i]);
      _ap(2 * i + 1, u[i]);
      u[i] = M::id();
      if (i == r - 1 + n >> hr)
        continue;
      i = r - 1 + n >> hr;
      _ap(2 * i, u[i]);
      _ap(2 * i + 1, u[i]);
      u[i] = M::id();
    }
    // for (int i = h; i; i--) {
    //   int j = (l + n) >> i;
    //   _ap(2 * j, u[j]);
    //   _ap(2 * j + 1, u[j]);
    //   u[j] = M::id();
    //   if (j == (r - 1 + n) >> i) continue;
    //   j = (r - 1 + n) >> i;
    //   _ap(2 * j, u[j]);
    //   _ap(2 * j + 1, u[j]);
    //   u[j] = M::id();
    // }
    for (int i = l + n, j = r + n; i < j; i >>= 1, j >>= 1) {
      if (i & 1)
        _ap(i++, f);
      if (j & 1)
        _ap(--j, f);
    }
    for (l += n; !(l & 1);)
      l >>= 1;
    while (l >>= 1)
      t[l] = M::op(t[2 * l], t[2 * l + 1]);
    for (r += n; !(r & 1);)
      r >>= 1;
    while (r >>= 1)
      t[r] = M::op(t[2 * r], t[2 * r + 1]);
  }
};

int main() {
  cin.tie(NULL);
  ios::sync_with_stdio(false);
  int n, q;
  cin >> n >> q;
  ST<M> st(n);
  for (int i = 0; i < n; i++)
    st.t[i + n].fill(numeric_limits<int>::max());
  st.build();
  for (int i = 0; i < q; i++) {
    int t;
    cin >> t;
    if (t) {
      int l, r;
      cin >> l >> r, r++;
      cout << st.get(l, r)[0] << '\\n';
    } else {
      int l, r, x;
      cin >> l >> r >> x, r++;
      st.set(l, r, M::U{0, x});
    }
  }
}