Problem p02763 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <cmath>
#include <complex>
#include <cstdint>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <regex>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;
using ll = long long;
using ull = unsigned long long;

namespace utils {
#define ALL(x) begin(x), end(x)
#define RALL(x) rbegin(x), rend(x)
template <class T, class Compare>
using p_queue = priority_queue<T, vector<T>, Compare>;
template <class T> using min_queue = p_queue<T, greater<T>>;
template <class T> using max_queue = p_queue<T, less<T>>;

template <class T> inline bool UPMIN(T &X, const T &A) {
  if (X > A) {
    X = A;
    return true;
  }
  return false;
}
template <class T> inline bool UPMAX(T &X, const T &A) {
  if (X < A) {
    X = A;
    return true;
  }
  return false;
}

template <class T> vector<T> VEC(int n, T t) { return vector<T>(n, t); }
template <class... Ts> auto VEC(int n, Ts... ts) {
  return vector<decltype(VEC(ts...))>(n, VEC(ts...));
}

template <class S, class T> istream &operator>>(istream &is, tuple<S, T> &t) {
  return is >> get<0>(t) >> get<1>(t);
}

template <class S, class T, class U>
istream &operator>>(istream &is, tuple<S, T, U> &t) {
  return is >> get<0>(t) >> get<1>(t) >> get<2>(t);
}

template <class S, class T>
ostream &operator<<(ostream &os, const tuple<S, T> &t) {
  return os << get<0>(t) << ' ' << get<1>(t);
}

template <class S, class T, class U>
ostream &operator<<(ostream &os, const tuple<S, T, U> &t) {
  return os << get<0>(t) << ' ' << get<1>(t) << ' ' << get<2>(t);
}

template <class T> istream &operator>>(istream &is, vector<T> &v) {
  for (auto &&x : v) {
    is >> x;
  }
  return is;
}

template <class T> ostream &operator<<(ostream &os, const vector<T> &v) {
  auto p = v.begin();
  assert(p != v.end());
  os << *p++;
  while (p != v.end()) {
    os << ' ' << *p++;
  }
  return os;
}

template <class T>
ostream &operator<<(ostream &os, const vector<vector<T>> &v) {
  auto p = v.begin();
  assert(p != v.end());
  os << *p++;
  while (p != v.end()) {
    os << '\n' << *p++;
  }
  return os;
}

template <class... Ts>
ostream &operator<<(ostream &os, const vector<tuple<Ts...>> &v) {
  auto p = v.begin();
  assert(p != v.end());
  os << *p++;
  while (p != v.end()) {
    os << '\n' << *p++;
  }
  return os;
}

constexpr long long INFLL = 1'000'000'000'000'000'000ll;
constexpr int INF = 1'000'000'000;
constexpr double PI = 3.14'159'265'358'973;
constexpr double EPS = 1e-10;
} // namespace utils
using namespace utils;

template <class Monoid> class SegmentTree {
  using Func = std::function<Monoid(Monoid, Monoid)>;
  int N;

  std::vector<Monoid> segment;

  const Func op;
  const Monoid id;

  bool dirty_flag;

public:
  // id : op = max なら -INT_MAX
  SegmentTree(int n, const Func biop, const Monoid &M1)
      : op(biop), id(M1), dirty_flag(false) {
    N = 1;
    while (N < n)
      N *= 2;
    segment.assign(2 * N, id);
  }

  void set(int k, const Monoid &a) {
    dirty_flag = true;
    segment[k + N] = a;
  }

  void build() {
    for (int k = N - 1; k > 0; --k) {
      segment[k] = op(segment[2 * k], segment[2 * k + 1]);
    } // end k
    dirty_flag = false;
  }

  void update(int k, const Monoid &a) {
    k += N;
    segment[k] = a;
    while (k /= 2) {
      segment[k] = op(segment[k * 2], segment[k * 2 + 1]);
    }
  }

  // -> op [a,b)
  Monoid query(unsigned a, unsigned b) {
    if (dirty_flag)
      build();
    dirty_flag = false;
    Monoid L = id, R = id;
    for (a += N, b += N; a < b; a >>= 1u, b >>= 1u) {
      if (a & 1u)
        L = op(L, segment[a++]);
      if (b & 1u)
        R = op(segment[--b], R);
    } // end i
    return op(L, R);
  }

  Monoid operator[](const int &k) const { return segment[k + N]; }
};

class solver {
  istream &is;
  ostream &os;

public:
  solver(istream &I, ostream &O) : is(I), os(O) {}

  int N, Q;
  string S;
  bool input() {
    is >> N >> S >> Q;
    return !!is;
  }

  void run();
};

int main(int argc, char *argv[]) {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << setprecision(16) << scientific;
#ifdef XELMH
  string test_cases = "test_B.txt";
  cerr << test_cases << " -->" << endl;
  auto fs = fstream(test_cases, fstream::in);
  int loop = 0;
  while (fs) {
    loop++;
    cout << '#' << loop << "#------\n";
    solver(fs, cout).run();
  }
  if (loop <= 1) {
    cout << "===" << endl;
    while (cin)
      solver(cin, cout).run();
  }
#else
  solver(cin, cout).run();
#endif
  return 0;
}

void solver::run() {
  if (!input())
    return;
  using alset = bitset<30>;
  SegmentTree<alset> seg(
      N, [](alset a, alset b) { return a | b; }, 0);

  vector<alset> als;
  als.reserve('z' - 'a' + 1);
  for (int al = 0; al < 'z' - 'a' + 1; ++al) {
    als.emplace_back(1 << al);
  } // end al

  for (int i = 0; i < N; ++i) {
    seg.set(i, als[S[i] - 'a']);
  } // end i

  for (int i = 0; i < Q; ++i) {
    int q;
    is >> q;
    if (q == 1) {
      int x;
      char c;
      is >> x >> c;
      seg.set(x - 1, als[c - 'a']);
    } else {
      int l, r;
      is >> l >> r;
      auto an = seg.query(l - 1, r);
      os << an.count() << endl;
    }
  } // end i
}


Fixed submission:
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <cmath>
#include <complex>
#include <cstdint>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <regex>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;
using ll = long long;
using ull = unsigned long long;

namespace utils {
#define ALL(x) begin(x), end(x)
#define RALL(x) rbegin(x), rend(x)
template <class T, class Compare>
using p_queue = priority_queue<T, vector<T>, Compare>;
template <class T> using min_queue = p_queue<T, greater<T>>;
template <class T> using max_queue = p_queue<T, less<T>>;

template <class T> inline bool UPMIN(T &X, const T &A) {
  if (X > A) {
    X = A;
    return true;
  }
  return false;
}
template <class T> inline bool UPMAX(T &X, const T &A) {
  if (X < A) {
    X = A;
    return true;
  }
  return false;
}

template <class T> vector<T> VEC(int n, T t) { return vector<T>(n, t); }
template <class... Ts> auto VEC(int n, Ts... ts) {
  return vector<decltype(VEC(ts...))>(n, VEC(ts...));
}

template <class S, class T> istream &operator>>(istream &is, tuple<S, T> &t) {
  return is >> get<0>(t) >> get<1>(t);
}

template <class S, class T, class U>
istream &operator>>(istream &is, tuple<S, T, U> &t) {
  return is >> get<0>(t) >> get<1>(t) >> get<2>(t);
}

template <class S, class T>
ostream &operator<<(ostream &os, const tuple<S, T> &t) {
  return os << get<0>(t) << ' ' << get<1>(t);
}

template <class S, class T, class U>
ostream &operator<<(ostream &os, const tuple<S, T, U> &t) {
  return os << get<0>(t) << ' ' << get<1>(t) << ' ' << get<2>(t);
}

template <class T> istream &operator>>(istream &is, vector<T> &v) {
  for (auto &&x : v) {
    is >> x;
  }
  return is;
}

template <class T> ostream &operator<<(ostream &os, const vector<T> &v) {
  auto p = v.begin();
  assert(p != v.end());
  os << *p++;
  while (p != v.end()) {
    os << ' ' << *p++;
  }
  return os;
}

template <class T>
ostream &operator<<(ostream &os, const vector<vector<T>> &v) {
  auto p = v.begin();
  assert(p != v.end());
  os << *p++;
  while (p != v.end()) {
    os << '\n' << *p++;
  }
  return os;
}

template <class... Ts>
ostream &operator<<(ostream &os, const vector<tuple<Ts...>> &v) {
  auto p = v.begin();
  assert(p != v.end());
  os << *p++;
  while (p != v.end()) {
    os << '\n' << *p++;
  }
  return os;
}

constexpr long long INFLL = 1'000'000'000'000'000'000ll;
constexpr int INF = 1'000'000'000;
constexpr double PI = 3.14'159'265'358'973;
constexpr double EPS = 1e-10;
} // namespace utils
using namespace utils;

template <class Monoid> class SegmentTree {
  using Func = std::function<Monoid(Monoid, Monoid)>;
  int N;

  std::vector<Monoid> segment;

  const Func op;
  const Monoid id;

  bool dirty_flag;

public:
  // id : op = max なら -INT_MAX
  SegmentTree(int n, const Func biop, const Monoid &M1)
      : op(biop), id(M1), dirty_flag(false) {
    N = 1;
    while (N < n)
      N *= 2;
    segment.assign(2 * N, id);
  }

  void set(int k, const Monoid &a) {
    dirty_flag = true;
    segment[k + N] = a;
  }

  void build() {
    for (int k = N - 1; k > 0; --k) {
      segment[k] = op(segment[2 * k], segment[2 * k + 1]);
    } // end k
    dirty_flag = false;
  }

  void update(int k, const Monoid &a) {
    k += N;
    segment[k] = a;
    while (k /= 2) {
      segment[k] = op(segment[k * 2], segment[k * 2 + 1]);
    }
  }

  // -> op [a,b)
  Monoid query(unsigned a, unsigned b) {
    if (dirty_flag)
      build();
    dirty_flag = false;
    Monoid L = id, R = id;
    for (a += N, b += N; a < b; a >>= 1u, b >>= 1u) {
      if (a & 1u)
        L = op(L, segment[a++]);
      if (b & 1u)
        R = op(segment[--b], R);
    } // end i
    return op(L, R);
  }

  Monoid operator[](const int &k) const { return segment[k + N]; }
};

class solver {
  istream &is;
  ostream &os;

public:
  solver(istream &I, ostream &O) : is(I), os(O) {}

  int N, Q;
  string S;
  bool input() {
    is >> N >> S >> Q;
    return !!is;
  }

  void run();
};

int main(int argc, char *argv[]) {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << setprecision(16) << scientific;
#ifdef XELMH
  string test_cases = "test_B.txt";
  cerr << test_cases << " -->" << endl;
  auto fs = fstream(test_cases, fstream::in);
  int loop = 0;
  while (fs) {
    loop++;
    cout << '#' << loop << "#------\n";
    solver(fs, cout).run();
  }
  if (loop <= 1) {
    cout << "===" << endl;
    while (cin)
      solver(cin, cout).run();
  }
#else
  solver(cin, cout).run();
#endif
  return 0;
}

void solver::run() {
  if (!input())
    return;
  using alset = bitset<30>;
  SegmentTree<alset> seg(
      N, [](alset a, alset b) { return a | b; }, 0);

  vector<alset> als;
  als.reserve('z' - 'a' + 1);
  for (int al = 0; al < 'z' - 'a' + 1; ++al) {
    als.emplace_back(1 << al);
  } // end al

  for (int i = 0; i < N; ++i) {
    seg.set(i, als[S[i] - 'a']);
  } // end i

  for (int i = 0; i < Q; ++i) {
    int q;
    is >> q;
    if (q == 1) {
      int x;
      char c;
      is >> x >> c;
      seg.update(x - 1, als[c - 'a']);
    } else {
      int l, r;
      is >> l >> r;
      auto an = seg.query(l - 1, r);
      os << an.count() << endl;
    }
  } // end i
}