Problem p03537 (C++) — buggy submission, verdict: Time Limit Exceeded

// need
#include <algorithm>
#include <iostream>
// data structure
#include <bitset>
#include <complex>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>
// #include <deque>
#include <array>
#include <unordered_map>
#include <unordered_set>
#include <valarray>
// stream
// #include <istream>
#include <sstream>
// #include <ostream>
#include <fstream>
// etc
#include <cassert>
#include <chrono>
#include <cmath>
#include <functional>
#include <iomanip>
#include <numeric>
#include <random>

// input
#define INIT                                                                   \\
  std::ios::sync_with_stdio(false);                                            \\
  std::cin.tie(0);
#define VAR(type, ...)                                                         \\
  type __VA_ARGS__;                                                            \\
  MACRO_VAR_Scan(__VA_ARGS__);
template <typename T> void MACRO_VAR_Scan(T &t) { std::cin >> t; }
template <typename First, typename... Rest>
void MACRO_VAR_Scan(First &first, Rest &...rest) {
  std::cin >> first;
  MACRO_VAR_Scan(rest...);
}
#define VEC_ROW(type, n, ...)                                                  \\
  std::vector<type> __VA_ARGS__;                                               \\
  MACRO_VEC_ROW_Init(n, __VA_ARGS__);                                          \\
  for (int w_ = 0; w_ < n; ++w_) {                                             \\
    MACRO_VEC_ROW_Scan(w_, __VA_ARGS__);                                       \\
  }
template <typename T> void MACRO_VEC_ROW_Init(int n, T &t) { t.resize(n); }
template <typename First, typename... Rest>
void MACRO_VEC_ROW_Init(int n, First &first, Rest &...rest) {
  first.resize(n);
  MACRO_VEC_ROW_Init(n, rest...);
}
template <typename T> void MACRO_VEC_ROW_Scan(int p, T &t) { std::cin >> t[p]; }
template <typename First, typename... Rest>
void MACRO_VEC_ROW_Scan(int p, First &first, Rest &...rest) {
  std::cin >> first[p];
  MACRO_VEC_ROW_Scan(p, rest...);
}
#define VEC(type, c, n)                                                        \\
  std::vector<type> c(n);                                                      \\
  for (auto &i : c)                                                            \\
    std::cin >> i;
#define MAT(type, c, m, n)                                                     \\
  std::vector<std::vector<type>> c(m, std::vector<type>(n));                   \\
  for (auto &R : c)                                                            \\
    for (auto &w : R)                                                          \\
      std::cin >> w;
// output
#define OUT(dist) std::cout << (dist);
#define FOUT(n, dist) std::cout << std::fixed << std::setprecision(n) << (dist);
#define SOUT(n, c, dist) std::cout << std::setw(n) << std::setfill(c) << (dist);
#define SP std::cout << " ";
#define TAB std::cout << "\\t";
#define BR std::cout << "\\n";
#define SPBR(w, n) std::cout << (w + 1 == n ? '\\n' : ' ');
#define ENDL std::cout << std::endl;
#define FLUSH std::cout << std::flush;
#define SHOW(dist)                                                             \\
  { std::cerr << #dist << "\\t:" << (dist) << "\\n"; }
#define SHOWVECTOR(v)                                                          \\
  {                                                                            \\
    std::cerr << #v << "\\t:";                                                  \\
    for (const auto &xxx : v) {                                                \\
      std::cerr << xxx << " ";                                                 \\
    }                                                                          \\
    std::cerr << "\\n";                                                         \\
  }
#define SHOWVECTOR2(v)                                                         \\
  {                                                                            \\
    std::cerr << #v << "\\t:\\n";                                                \\
    for (const auto &xxx : v) {                                                \\
      for (const auto &yyy : xxx) {                                            \\
        std::cerr << yyy << " ";                                               \\
      }                                                                        \\
      std::cerr << "\\n";                                                       \\
    }                                                                          \\
  }
#define SHOWQUEUE(a)                                                           \\
  {                                                                            \\
    auto tmp(a);                                                               \\
    std::cerr << #a << "\\t:";                                                  \\
    while (!tmp.empty()) {                                                     \\
      std::cerr << tmp.front() << " ";                                         \\
      tmp.pop();                                                               \\
    }                                                                          \\
    std::cerr << "\\n";                                                         \\
  }
// utility
#define ALL(a) (a).begin(), (a).end()
#define FOR(w, a, n) for (int w = (a); w < (n); ++w)
#define RFOR(w, a, n) for (int w = (n)-1; w >= (a); --w)
#define REP(w, n) for (int w = 0; w < int(n); ++w)
#define RREP(w, n) for (int w = int(n) - 1; w >= 0; --w)
#define FORLL(w, a, n) for (ll w = ll(a); w < ll(n); ++w)
#define RFORLL(w, a, n) for (ll w = ll(n) - 1; w >= ll(a); --w)
#define REPLL(w, n) for (ll w = 0; w < ll(n); ++w)
#define RREPLL(w, n) for (ll w = ll(n) - 1; w >= 0; --w)
#define IN(a, x, b) (a <= x && x < b)
template <class T> inline T CHMAX(T &a, const T b) {
  return a = (a < b) ? b : a;
}
template <class T> inline T CHMIN(T &a, const T b) {
  return a = (a > b) ? b : a;
}
#define EXCEPTION(msg)                                                         \\
  throw std::string("Exception : " msg " [ in ") + __func__ + " : " +          \\
      std::to_string(__LINE__) + " lines ]"
#define TRY(cond, msg)                                                         \\
  try {                                                                        \\
    if (cond)                                                                  \\
      EXCEPTION(msg);                                                          \\
  } catch (std::string s) {                                                    \\
    std::cerr << s << std::endl;                                               \\
  }
// void CHECKTIME(std::function<void()> f) { auto start =
// std::chrono::system_clock::now(); f(); auto end =
// std::chrono::system_clock::now(); auto res =
// std::chrono::duration_cast<std::chrono::nanoseconds>((end - start)).count();
// std::cerr << "[Time:" << res << "ns  (" << res / (1.0e9) << "s)]\\n"; }
//  test
template <class T> using V = std::vector<T>;
template <class T> using VV = V<V<T>>;

template <typename S, typename T>
std::ostream &operator<<(std::ostream &os, std::pair<S, T> p) {
  os << "(" << p.first << ", " << p.second << ")";
  return os;
}

#define random_shuffle "USE std::shuffle!";

// type/const
#define int ll
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using PAIR = std::pair<int, int>;
using PAIRLL = std::pair<ll, ll>;
constexpr int INFINT = 1 << 30;                         // 1.07x10^ 9
constexpr int INFINT_LIM = (1LL << 31) - 1;             // 2.15x10^ 9
constexpr ll INFLL = 1LL << 60;                         // 1.15x10^18
constexpr ll INFLL_LIM = (1LL << 62) - 1 + (1LL << 62); // 9.22x10^18
constexpr double EPS = 1e-6;
constexpr int MOD = 998244353;
constexpr double PI = 3.141592653589793238462643383279;
template <class T, size_t N> void FILL(T (&a)[N], const T &val) {
  for (auto &x : a)
    x = val;
}
template <class ARY, size_t N, size_t M, class T>
void FILL(ARY (&a)[N][M], const T &val) {
  for (auto &b : a)
    FILL(b, val);
}
template <class T> void FILL(std::vector<T> &a, const T &val) {
  for (auto &x : a)
    x = val;
}
template <class ARY, class T>
void FILL(std::vector<std::vector<ARY>> &a, const T &val) {
  for (auto &b : a)
    FILL(b, val);
}
// ------------>8------------------------------------->8------------

void add(char &c, int d) {
  int t = c - 'a' + d;
  t %= 26;
  if (t < 0)
    t += 26;
  c = 'a' + t;
}

bool calc() {
  VAR(std::string, s);
  VAR(int, n);
  VEC_ROW(int, n, l, r);

  std::string t(s.rbegin(), s.rend());
  int M = s.size();
  int m = M / 2;
  s.resize(m);
  t.resize(m);

  std::vector<std::set<int>> segset(m + 1);
  std::vector<int> seg(m + 1, -1);

  REP(i, n) {
    --l[i];
    --r[i];
    if (r[i] < m)
      continue;
    if (l[i] >= M - m) {
      l[i] = M - 1 - l[i];
      r[i] = M - 1 - r[i];
      std::swap(l[i], r[i]);
      continue;
    }
    r[i] = M - 1 - r[i];
    if (l[i] == r[i]) {
      l[i] = r[i] = -1;
    } else if (l[i] < r[i]) {
      --r[i];
    } else if (r[i] < l[i]) {
      --l[i];
      std::swap(l[i], r[i]);
    }
  }

  REP(i, n) {
    if (l[i] == -1)
      continue;
    segset[l[i]].insert(r[i]);
  }

  REP(i, m) {
    int pre = -1;
    for (auto &x : segset[i]) {
      if (pre != -1) {
        if (pre + 1 <= x)
          segset[pre + 1].insert(x);
      }
      pre = x;
    }
    if (!segset[i].empty()) {
      seg[i] = *segset[i].begin();
    }
    segset[i].clear();
  }

  std::vector<int> imos(m + 1, 0);
  REP(i, m) {
    add(s[i], imos[i]);
    if (s[i] != t[i]) {
      if (seg[i] == -1)
        return false;

      int d = t[i] - s[i];
      if (d < 0)
        d += 26;
      add(s[i], d);
      assert(s[i] == t[i]);

      imos[i] += d;
      imos[seg[i] + 1] -= d;
    }
    (imos[i + 1] += imos[i]) %= 26;
  }
  assert(s == t);

  return true;
}

signed main() {
  INIT;

  OUT(calc() ? "YES" : "NO") BR;

  return 0;
}

Error: TLE

Fixed submission:

// need
#include <algorithm>
#include <iostream>
// data structure
#include <bitset>
#include <complex>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>
// #include <deque>
#include <array>
#include <unordered_map>
#include <unordered_set>
#include <valarray>
// stream
// #include <istream>
#include <sstream>
// #include <ostream>
#include <fstream>
// etc
#include <cassert>
#include <chrono>
#include <cmath>
#include <functional>
#include <iomanip>
#include <numeric>
#include <random>

// input
#define INIT                                                                   \\
  std::ios::sync_with_stdio(false);                                            \\
  std::cin.tie(0);
#define VAR(type, ...)                                                         \\
  type __VA_ARGS__;                                                            \\
  MACRO_VAR_Scan(__VA_ARGS__);
template <typename T> void MACRO_VAR_Scan(T &t) { std::cin >> t; }
template <typename First, typename... Rest>
void MACRO_VAR_Scan(First &first, Rest &...rest) {
  std::cin >> first;
  MACRO_VAR_Scan(rest...);
}
#define VEC_ROW(type, n, ...)                                                  \\
  std::vector<type> __VA_ARGS__;                                               \\
  MACRO_VEC_ROW_Init(n, __VA_ARGS__);                                          \\
  for (int w_ = 0; w_ < n; ++w_) {                                             \\
    MACRO_VEC_ROW_Scan(w_, __VA_ARGS__);                                       \\
  }
template <typename T> void MACRO_VEC_ROW_Init(int n, T &t) { t.resize(n); }
template <typename First, typename... Rest>
void MACRO_VEC_ROW_Init(int n, First &first, Rest &...rest) {
  first.resize(n);
  MACRO_VEC_ROW_Init(n, rest...);
}
template <typename T> void MACRO_VEC_ROW_Scan(int p, T &t) { std::cin >> t[p]; }
template <typename First, typename... Rest>
void MACRO_VEC_ROW_Scan(int p, First &first, Rest &...rest) {
  std::cin >> first[p];
  MACRO_VEC_ROW_Scan(p, rest...);
}
#define VEC(type, c, n)                                                        \\
  std::vector<type> c(n);                                                      \\
  for (auto &i : c)                                                            \\
    std::cin >> i;
#define MAT(type, c, m, n)                                                     \\
  std::vector<std::vector<type>> c(m, std::vector<type>(n));                   \\
  for (auto &R : c)                                                            \\
    for (auto &w : R)                                                          \\
      std::cin >> w;
// output
#define OUT(dist) std::cout << (dist);
#define FOUT(n, dist) std::cout << std::fixed << std::setprecision(n) << (dist);
#define SOUT(n, c, dist) std::cout << std::setw(n) << std::setfill(c) << (dist);
#define SP std::cout << " ";
#define TAB std::cout << "\\t";
#define BR std::cout << "\\n";
#define SPBR(w, n) std::cout << (w + 1 == n ? '\\n' : ' ');
#define ENDL std::cout << std::endl;
#define FLUSH std::cout << std::flush;
#define SHOW(dist)                                                             \\
  { std::cerr << #dist << "\\t:" << (dist) << "\\n"; }
#define SHOWVECTOR(v)                                                          \\
  {                                                                            \\
    std::cerr << #v << "\\t:";                                                  \\
    for (const auto &xxx : v) {                                                \\
      std::cerr << xxx << " ";                                                 \\
    }                                                                          \\
    std::cerr << "\\n";                                                         \\
  }
#define SHOWVECTOR2(v)                                                         \\
  {                                                                            \\
    std::cerr << #v << "\\t:\\n";                                                \\
    for (const auto &xxx : v) {                                                \\
      for (const auto &yyy : xxx) {                                            \\
        std::cerr << yyy << " ";                                               \\
      }                                                                        \\
      std::cerr << "\\n";                                                       \\
    }                                                                          \\
  }
#define SHOWQUEUE(a)                                                           \\
  {                                                                            \\
    auto tmp(a);                                                               \\
    std::cerr << #a << "\\t:";                                                  \\
    while (!tmp.empty()) {                                                     \\
      std::cerr << tmp.front() << " ";                                         \\
      tmp.pop();                                                               \\
    }                                                                          \\
    std::cerr << "\\n";                                                         \\
  }
// utility
#define ALL(a) (a).begin(), (a).end()
#define FOR(w, a, n) for (int w = (a); w < (n); ++w)
#define RFOR(w, a, n) for (int w = (n)-1; w >= (a); --w)
#define REP(w, n) for (int w = 0; w < int(n); ++w)
#define RREP(w, n) for (int w = int(n) - 1; w >= 0; --w)
#define FORLL(w, a, n) for (ll w = ll(a); w < ll(n); ++w)
#define RFORLL(w, a, n) for (ll w = ll(n) - 1; w >= ll(a); --w)
#define REPLL(w, n) for (ll w = 0; w < ll(n); ++w)
#define RREPLL(w, n) for (ll w = ll(n) - 1; w >= 0; --w)
#define IN(a, x, b) (a <= x && x < b)
template <class T> inline T CHMAX(T &a, const T b) {
  return a = (a < b) ? b : a;
}
template <class T> inline T CHMIN(T &a, const T b) {
  return a = (a > b) ? b : a;
}
#define EXCEPTION(msg)                                                         \\
  throw std::string("Exception : " msg " [ in ") + __func__ + " : " +          \\
      std::to_string(__LINE__) + " lines ]"
#define TRY(cond, msg)                                                         \\
  try {                                                                        \\
    if (cond)                                                                  \\
      EXCEPTION(msg);                                                          \\
  } catch (std::string s) {                                                    \\
    std::cerr << s << std::endl;                                               \\
  }
// void CHECKTIME(std::function<void()> f) { auto start =
// std::chrono::system_clock::now(); f(); auto end =
// std::chrono::system_clock::now(); auto res =
// std::chrono::duration_cast<std::chrono::nanoseconds>((end - start)).count();
// std::cerr << "[Time:" << res << "ns  (" << res / (1.0e9) << "s)]\\n"; }
//  test
template <class T> using V = std::vector<T>;
template <class T> using VV = V<V<T>>;

template <typename S, typename T>
std::ostream &operator<<(std::ostream &os, std::pair<S, T> p) {
  os << "(" << p.first << ", " << p.second << ")";
  return os;
}

#define random_shuffle "USE std::shuffle!";

// type/const
#define int ll
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using PAIR = std::pair<int, int>;
using PAIRLL = std::pair<ll, ll>;
constexpr int INFINT = 1 << 30;                         // 1.07x10^ 9
constexpr int INFINT_LIM = (1LL << 31) - 1;             // 2.15x10^ 9
constexpr ll INFLL = 1LL << 60;                         // 1.15x10^18
constexpr ll INFLL_LIM = (1LL << 62) - 1 + (1LL << 62); // 9.22x10^18
constexpr double EPS = 1e-6;
constexpr int MOD = 998244353;
constexpr double PI = 3.141592653589793238462643383279;
template <class T, size_t N> void FILL(T (&a)[N], const T &val) {
  for (auto &x : a)
    x = val;
}
template <class ARY, size_t N, size_t M, class T>
void FILL(ARY (&a)[N][M], const T &val) {
  for (auto &b : a)
    FILL(b, val);
}
template <class T> void FILL(std::vector<T> &a, const T &val) {
  for (auto &x : a)
    x = val;
}
template <class ARY, class T>
void FILL(std::vector<std::vector<ARY>> &a, const T &val) {
  for (auto &b : a)
    FILL(b, val);
}
// ------------>8------------------------------------->8------------

void add(char &c, int d) {
  int t = c - 'a' + d;
  t %= 26;
  if (t < 0)
    t += 26;
  c = 'a' + t;
}

bool calc() {
  VAR(std::string, s);
  VAR(int, n);
  VEC_ROW(int, n, l, r);

  std::string t(s.rbegin(), s.rend());
  int M = s.size();
  int m = M / 2;
  s.resize(m);
  t.resize(m);

  std::vector<std::vector<int>> seg(m + 1);

  REP(i, n) {
    --l[i];
    --r[i];
    if (r[i] < m)
      continue;
    if (l[i] >= M - m) {
      l[i] = M - 1 - l[i];
      r[i] = M - 1 - r[i];
      std::swap(l[i], r[i]);
      continue;
    }
    r[i] = M - 1 - r[i];
    if (l[i] == r[i]) {
      l[i] = r[i] = -1;
    } else if (l[i] < r[i]) {
      --r[i];
    } else if (r[i] < l[i]) {
      --l[i];
      std::swap(l[i], r[i]);
    }
  }

  REP(i, n) {
    if (l[i] == -1)
      continue;
    seg[l[i]].emplace_back(r[i]);
  }

  REP(i, m) {
    std::sort(ALL(seg[i]));
    FOR(j, 1, seg[i].size()) {
      if (seg[i][0] + 1 <= seg[i][j])
        seg[seg[i][0] + 1].emplace_back(seg[i][j]);
    }
    if (seg[i].size() > 1)
      seg[i].resize(1);
  }

  std::vector<int> imos(m + 1, 0);
  REP(i, m) {
    add(s[i], imos[i]);
    if (s[i] != t[i]) {
      if (seg[i].empty())
        return false;

      int d = t[i] - s[i];
      if (d < 0)
        d += 26;
      add(s[i], d);
      assert(s[i] == t[i]);

      imos[i] += d;
      imos[seg[i][0] + 1] -= d;
    }
    (imos[i + 1] += imos[i]) %= 26;
  }
  assert(s == t);

  return true;
}

signed main() {
  INIT;

  OUT(calc() ? "YES" : "NO") BR;

  return 0;
}