meowpp/dsa/BinaryIndexTree.hpp


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namespace meow{
  template<class Value>
  inline
  BinaryIndexTree<Value>::BinaryIndexTree():
  _array(0){
  }
  template<class Value>
  inline
  BinaryIndexTree<Value>::BinaryIndexTree(size_t __size, Value const& __value):
  _array(__size, __value){
  }
  template<class Value>
  inline
  BinaryIndexTree<Value>::BinaryIndexTree(BinaryIndexTree const& __tree2):
  _array(__tree2._array){
  }
  //
  template<class Value>
  inline void
  BinaryIndexTree<Value>::reset(size_t __size, Value const& __init){
    _array.clear();
    _array.resize(__size, __init);
  }
  //
  template<class Value>
  inline void
  BinaryIndexTree<Value>::update(size_t __index, Value const& __value){
    __index++;
    for( ; __index <= _array.size(); __index += (__index & -__index)){
      _array[__index - 1] = _array[__index - 1] +  __value;
    }
  }
  template<class Value>
  inline Value
  BinaryIndexTree<Value>::query(ssize_t __index) const{
    __index = std::min(__index + 1, (ssize_t)_array.size());
    Value ret(0);
    for( ; 0 < __index; __index -= (__index & -__index)){
      ret = ret + _array[__index - 1];
    }
    return ret;
  }
}