Problem p02346 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
using namespace std;

template <class T> struct treap {
#define treapInf INT_MAX

public:
  struct node {
    T val;
    node *lch, *rch;
    int pri, sz;
    T sum, mini;

    node(T val, int pri) : val(val), pri(pri), sz(1), sum(val), mini(val) {
      lch = rch = NULL;
    }
  };

  node *root;
  treap() : root(NULL) { srand(time(NULL)); }

private:
  inline int size(node *t) { return !t ? 0 : t->sz; }
  inline T sum(node *t) { return !t ? 0 : t->sum; }
  inline T mini(node *t) { return !t ? treapInf : t->mini; }

  node *update(node *t) {
    // if(!t)return t;
    t->sz = size(t->lch) + size(t->rch) + 1;
    t->sum = sum(t->lch) + sum(t->rch) + t->val;
    t->mini = min(min(mini(t->lch), mini(t->rch)), t->val);
    return t;
  }

  node *merge(node *l, node *r) {
    if (!l || !r)
      return l ? l : r;

    if (l->pri > r->pri) {
      l->rch = merge(l->rch, r);
      return update(l);
    } else {
      r->lch = merge(l, r->lch);
      return update(r);
    }
  }

  pair<node *, node *> split(node *t, int k) {
    if (!t)
      return make_pair((node *)NULL, (node *)NULL);

    if (k <= size(t->lch)) {
      pair<node *, node *> s = split(t->lch, k);
      t->lch = s.second;
      return make_pair(s.first, update(t));
    } else {
      pair<node *, node *> s = split(t->rch, k - size(t->lch) - 1);
      t->rch = s.first;
      return make_pair(update(t), s.second);
    }
  }

  node *insert(node *t, int k, T val, int pri) {
    pair<node *, node *> s = split(t, k);
    t = merge(s.first, new node(val, pri));
    t = merge(t, s.second);
    return update(t);
  }

  node *erase(node *t, int k) {
    pair<node *, node *> s1, s2;
    s2 = split(t, k + 1);
    s1 = split(s2.first, k);
    return update(t = merge(s1.first, s2.second));
  }

  node *find(node *t, int k) {
    // if(!t)return t;
    int c = size(t->lch);
    if (k < c)
      return find(t->lch, k);
    if (k == c)
      return t;
    return find(t->rch, k - c - 1);
  }

  T rangeMinimumQuery(int l, int r, node *t) {
    int sz = size(t);
    if (r <= 0 || sz <= l)
      return treapInf;
    if (l <= 0 && sz <= r)
      return mini(t);

    sz = size(t->lch);
    T vl = rangeMinimumQuery(l, r, t->lch);
    T vr = rangeMinimumQuery(l - sz - 1, r - sz - 1, t->rch);
    T res = min(vl, vr);
    if (l <= sz && sz < r)
      res = min(res, t->val);
    return res;
  }

  T rangeSumQuery(int l, int r, node *t) {
    int sz = size(t);
    if (r <= 0 || sz <= l)
      return 0;
    if (l <= 0 && sz <= r)
      return sum(t);

    sz = size(t->lch);
    T vl = rangeSumQuery(l, r, t->lch);
    T vr = rangeSumQuery(l - sz - 1, r - sz - 1, t->rch);
    T res = vl + vr;
    if (l <= sz && sz < r)
      res += t->val;
    return res;
  }

  void debug(node *t) {
    if (!t)
      return;
    debug(t->lch);
    cout << t->val << " ";
    debug(t->rch);
  }

public:
  void insert(int k, T val) { root = insert(root, k, val, rand()); }
  void erase(int k) { root = erase(root, k); }
  node *find(int k) { return find(root, k); }

  void add(int k, T v) {
    node *a = find(k);
    T tmp = a->val;
    erase(k);
    insert(k, tmp + v);
  }

  void update(int k, T v) {
    erase(k);
    insert(k, v);
  }

  T rangeMinimumQuery(int l, int r) { return rangeMinimumQuery(l, r, root); }

  T rangeSumQuery(int l, int r) { return rangeSumQuery(l, r, root); }

  void debug() {
    debug(root);
    cout << endl;
  }
};

int main() {

  int n, q;
  cin >> n >> q;

  treap<int> t;

  for (int i = 0; i < n; i++)
    t.insert(i, 0);

  while (q--) {
    int com, x, y;
    cin >> com >> x >> y;
    x--;
    if (com == 0) {
      t.add(x, y);
    } else {
      cout << t.rangeSumQuery(x, y) << endl;
    }
  }

  return 0;
}

Fixed submission:
#include <bits/stdc++.h>
using namespace std;

template <class T> struct treap {
#define treapInf INT_MAX

public:
  struct node {
    T val;
    node *lch, *rch;
    int pri, sz;
    T sum, mini;

    node(T val, int pri) : val(val), pri(pri), sz(1), sum(val), mini(val) {
      lch = rch = NULL;
    }
  };

  node *root;
  treap() : root(NULL) { srand(time(NULL)); }

private:
  inline int size(node *t) { return !t ? 0 : t->sz; }
  inline T sum(node *t) { return !t ? 0 : t->sum; }
  inline T mini(node *t) { return !t ? treapInf : t->mini; }

  node *update(node *t) {
    if (!t)
      return t;
    t->sz = size(t->lch) + size(t->rch) + 1;
    t->sum = sum(t->lch) + sum(t->rch) + t->val;
    t->mini = min(min(mini(t->lch), mini(t->rch)), t->val);
    return t;
  }

  node *merge(node *l, node *r) {
    if (!l || !r)
      return l ? l : r;

    if (l->pri > r->pri) {
      l->rch = merge(l->rch, r);
      return update(l);
    } else {
      r->lch = merge(l, r->lch);
      return update(r);
    }
  }

  pair<node *, node *> split(node *t, int k) {
    if (!t)
      return make_pair((node *)NULL, (node *)NULL);

    if (k <= size(t->lch)) {
      pair<node *, node *> s = split(t->lch, k);
      t->lch = s.second;
      return make_pair(s.first, update(t));
    } else {
      pair<node *, node *> s = split(t->rch, k - size(t->lch) - 1);
      t->rch = s.first;
      return make_pair(update(t), s.second);
    }
  }

  node *insert(node *t, int k, T val, int pri) {
    pair<node *, node *> s = split(t, k);
    t = merge(s.first, new node(val, pri));
    t = merge(t, s.second);
    return update(t);
  }

  node *erase(node *t, int k) {
    pair<node *, node *> s1, s2;
    s2 = split(t, k + 1);
    s1 = split(s2.first, k);
    return update(t = merge(s1.first, s2.second));
  }

  node *find(node *t, int k) {
    // if(!t)return t;
    int c = size(t->lch);
    if (k < c)
      return find(t->lch, k);
    if (k == c)
      return t;
    return find(t->rch, k - c - 1);
  }

  T rangeMinimumQuery(int l, int r, node *t) {
    int sz = size(t);
    if (r <= 0 || sz <= l)
      return treapInf;
    if (l <= 0 && sz <= r)
      return mini(t);

    sz = size(t->lch);
    T vl = rangeMinimumQuery(l, r, t->lch);
    T vr = rangeMinimumQuery(l - sz - 1, r - sz - 1, t->rch);
    T res = min(vl, vr);
    if (l <= sz && sz < r)
      res = min(res, t->val);
    return res;
  }

  T rangeSumQuery(int l, int r, node *t) {
    int sz = size(t);
    if (r <= 0 || sz <= l)
      return 0;
    if (l <= 0 && sz <= r)
      return sum(t);

    sz = size(t->lch);
    T vl = rangeSumQuery(l, r, t->lch);
    T vr = rangeSumQuery(l - sz - 1, r - sz - 1, t->rch);
    T res = vl + vr;
    if (l <= sz && sz < r)
      res += t->val;
    return res;
  }

  void debug(node *t) {
    if (!t)
      return;
    debug(t->lch);
    cout << t->val << " ";
    debug(t->rch);
  }

public:
  void insert(int k, T val) { root = insert(root, k, val, rand()); }
  void erase(int k) { root = erase(root, k); }
  node *find(int k) { return find(root, k); }

  void add(int k, T v) {
    node *a = find(k);
    T tmp = a->val;
    erase(k);
    insert(k, tmp + v);
  }

  void update(int k, T v) {
    erase(k);
    insert(k, v);
  }

  T rangeMinimumQuery(int l, int r) { return rangeMinimumQuery(l, r, root); }

  T rangeSumQuery(int l, int r) { return rangeSumQuery(l, r, root); }

  void debug() {
    debug(root);
    cout << endl;
  }
};

int main() {

  int n, q;
  cin >> n >> q;

  treap<int> t;

  for (int i = 0; i < n; i++)
    t.insert(i, 0);

  while (q--) {
    int com, x, y;
    cin >> com >> x >> y;
    x--;
    if (com == 0) {
      t.add(x, y);
    } else {
      cout << t.rangeSumQuery(x, y) << endl;
    }
  }

  return 0;
}