Problem p02345 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>

// Shrotening
#define fst first
#define snd second
#define pb push_back

// Loop
#define FOR(i, a, b) for (long i = (a); i < (b); ++i)
#define RFOR(i, a, b) for (long i = (a); i >= (b); --i)

#define REP(i, a) for (long i = 0; i < (a); ++i)
#define RREP(i, a) for (long i = (a); i >= 0; --i)

#define EACH(i, a) for (auto(i) = (a).begin(), _END = (a).end(); i != _END; ++i)
#define REACH(i, a)                                                            \\
  for (auto(i) = (a).rbegin(), _END = (a).rend(); i != _END; ++i)

// Algorithm
#define ALL(a) (a).begin(), a.end()
#define RALL(a) (a).rbegin(), a.rend()
#define EXIST(a, x) ((a).find(x) != (a).end())
#define SORT(a) std::sort((a).begin(), (a).end())
#define UNIQUE(a)                                                              \\
  std::sort((a).begin(), a.end()),                                             \\
      a.erase(std::unique((a).begin(), a.end()), a.end());
#define SUM(a) std::accumulate((a).begin(), (a).end(), 0);

// Setting
#define OPT                                                                    \\
  std::cin.tie(0);                                                             \\
  std::ios::sync_with_stdio(false);

// debug message
bool debug = true;
#define MSG(s)                                                                 \\
  if (debug) {                                                                 \\
    std::cout << s << std::endl;                                               \\
  }
#define DEBUG(x)                                                               \\
  if (debug) {                                                                 \\
    std::cout << "debug(" << #x << "): " << x << std::endl;                    \\
  }

// alias
typedef long long LL;
typedef std::vector<char> VC;
typedef std::vector<int> VI;
typedef std::vector<long> VL;
typedef std::vector<long long> VLL;

typedef std::vector<VC> VC2;
typedef std::vector<VI> VI2;
typedef std::vector<VL> VL2;
typedef std::vector<VLL> VLL2;

typedef std::pair<int, int> PII;

template <class T> struct SegTree {
  // tree: data structure
  // INF: initilize value
  // f: update function(old, new)
  // g: get function(child1, child2)

  T INF;
  size_t N;
  std::vector<T> tree;

  std::function<T(T, T)> F;
  std::function<T(T, T)> G;

  SegTree(size_t size, T inf, std::function<T(T, T)> f,
          std::function<T(T, T)> g) {
    INF = inf;
    F = f;
    G = g;

    N = 1;
    while (N < size) {
      N <<= 1;
    }
    tree.resize(2 * N - 1, INF);
  }

  void update(int i, int x) {
    i += N - 1;
    tree[i] = F(tree[i], x);
    while (i > 0) {
      i = (i - 1) / 2;
      tree[i] = G(tree[i * 2 + 1], tree[i * 2 + 2]);
    }
  }

  T query(size_t a, size_t b) {
    auto x = query(a, b, 0, 0, N);
    return x;
  }
  T query(size_t a, size_t b, size_t k, size_t l, size_t r) {
    if (r <= a || b <= l) {
      return INF;
    }
    if (a <= l && r <= b) {
      return tree[k];
    } else {
      T vl = query(a, b, k * 2 + 1, l, (l + r) / 2);
      T vr = query(a, b, k * 2 + 2, (l + r) / 2, r);
      return G(vl, vr);
    }
  }

  void debug() {
    std::cout << "------" << std::endl;
    std::cout << tree[0] << std::endl;
    size_t r = 0;
    while (r < N - 1) {
      size_t ch = r * 2 + 2;
      FOR(i, r + 1, ch + 1) {
        if (i != r + 1)
          std::cout << " ";
        std::cout << tree[i];
      }
      std::cout << std::endl;
      r = ch;
    }
    std::cout << "------" << std::endl;
  }
};

int N, Q;
int main() {
  std::cin >> N >> Q;
  SegTree<long> st = SegTree<long>(
      N, (1LL << 31) - 1, [](long a, long b) { return b; },
      [](long a, long b) { return a < b ? a : b; });

  REP(i, Q) {
    long c, x, y;
    std::cin >> c >> x >> y;
    if (c == 0) {
      st.update(x, y);
    } else {
      std::cout << st.query(x, y + 1) << std::endl;
    }
  }
}

Error: WA

Fixed submission:

#include <bits/stdc++.h>

// Shrotening
#define fst first
#define snd second
#define pb push_back

// Loop
#define FOR(i, a, b) for (long i = (a); i < (b); ++i)
#define RFOR(i, a, b) for (long i = (a); i >= (b); --i)

#define REP(i, a) for (long i = 0; i < (a); ++i)
#define RREP(i, a) for (long i = (a); i >= 0; --i)

#define EACH(i, a) for (auto(i) = (a).begin(), _END = (a).end(); i != _END; ++i)
#define REACH(i, a)                                                            \\
  for (auto(i) = (a).rbegin(), _END = (a).rend(); i != _END; ++i)

// Algorithm
#define ALL(a) (a).begin(), a.end()
#define RALL(a) (a).rbegin(), a.rend()
#define EXIST(a, x) ((a).find(x) != (a).end())
#define SORT(a) std::sort((a).begin(), (a).end())
#define UNIQUE(a)                                                              \\
  std::sort((a).begin(), a.end()),                                             \\
      a.erase(std::unique((a).begin(), a.end()), a.end());
#define SUM(a) std::accumulate((a).begin(), (a).end(), 0);

// Setting
#define OPT                                                                    \\
  std::cin.tie(0);                                                             \\
  std::ios::sync_with_stdio(false);

// debug message
bool debug = true;
#define MSG(s)                                                                 \\
  if (debug) {                                                                 \\
    std::cout << s << std::endl;                                               \\
  }
#define DEBUG(x)                                                               \\
  if (debug) {                                                                 \\
    std::cout << "debug(" << #x << "): " << x << std::endl;                    \\
  }

// alias
typedef long long LL;
typedef std::vector<char> VC;
typedef std::vector<int> VI;
typedef std::vector<long> VL;
typedef std::vector<long long> VLL;

typedef std::vector<VC> VC2;
typedef std::vector<VI> VI2;
typedef std::vector<VL> VL2;
typedef std::vector<VLL> VLL2;

typedef std::pair<int, int> PII;

template <class T> struct SegTree {
  // tree: data structure
  // INF: initilize value
  // f: update function(old, new)
  // g: get function(child1, child2)

  T INF;
  size_t N;
  std::vector<T> tree;

  std::function<T(T, T)> F;
  std::function<T(T, T)> G;

  SegTree(size_t size, T inf, std::function<T(T, T)> f,
          std::function<T(T, T)> g) {
    INF = inf;
    F = f;
    G = g;

    N = 1;
    while (N < size) {
      N <<= 1;
    }
    tree.resize(2 * N - 1, INF);
  }

  void update(int i, int x) {
    i += N - 1;
    tree[i] = F(tree[i], x);
    while (i > 0) {
      i = (i - 1) / 2;
      tree[i] = G(tree[i * 2 + 1], tree[i * 2 + 2]);
    }
  }

  T query(size_t a, size_t b) {
    auto x = query(a, b, 0, 0, N);
    return x;
  }
  T query(size_t a, size_t b, size_t k, size_t l, size_t r) {
    if (r <= a || b <= l) {
      return INF;
    }
    if (a <= l && r <= b) {
      return tree[k];
    } else {
      T vl = query(a, b, k * 2 + 1, l, (l + r) / 2);
      T vr = query(a, b, k * 2 + 2, (l + r) / 2, r);
      return G(vl, vr);
    }
  }

  void debug() {
    std::cout << "------" << std::endl;
    std::cout << tree[0] << std::endl;
    size_t r = 0;
    while (r < N - 1) {
      size_t ch = r * 2 + 2;
      FOR(i, r + 1, ch + 1) {
        if (i != r + 1)
          std::cout << " ";
        std::cout << tree[i];
      }
      std::cout << std::endl;
      r = ch;
    }
    std::cout << "------" << std::endl;
  }
};

int N, Q;
int main() {
  std::cin >> N >> Q;
  SegTree<long> st = SegTree<long>(
      N, (1LL << 31) - 1, [](long a, long b) { return a + b; },
      [](long a, long b) { return a + b; });

  REP(i, Q) {
    long c, x, y;
    std::cin >> c >> x >> y;
    if (c == 0) {
      st.update(x - 1, y);
    } else {
      std::cout << st.query(x - 1, y) << std::endl;
    }
  }
}