{
  "Class_Array_tree": {
    "prefix": "Class_Array_tree",
    "body": [
      "",
      "template <class T>",
      "class Array_tree {",
      " public:",
      "  Array_tree() {}",
      "  Array_tree(int n) { this->n = n, tree = vector<T>(n + 1); }",
      "  void add(int id, T key) {",
      "    for (int i = id; i <= n; i += lowbit(i)) tree[i] += key;",
      "  }",
      "",
      "  T get_sum(int id) {",
      "    T sum = 0;",
      "    for (int i = id; i; i -= lowbit(i)) sum += tree[i];",
      "    return sum;",
      "  }",
      "",
      "  T get_sum(int l, int r) { return get_sum(r) - get_sum(l - 1); }",
      "",
      " private:",
      "  int n;",
      "  vector<T> tree;",
      "  int lowbit(int x) { return x & -x; }",
      "};",
      ""
    ]
  }
}
}