C ++ real-source code analysis and algorithm source code analysis

C ++ real-source code analysis and algorithm source code analysis

Schemdes:

// TEMPLATE FUNCTION includes WITH PREDtemplate<class _InIt1,    class _InIt2,    class _Pr> inline    bool _Includes(_InIt1 _First1, _InIt1 _Last1,        _InIt2 _First2, _InIt2 _Last2, _Pr _Pred)    {    // test if set [_First1, _Last1) in [_First2, _Last2), using _Pred    for (; _First1 != _Last1 && _First2 != _Last2; )        if (_DEBUG_LT_PRED(_Pred, *_First2, *_First1))            return (false);        else if (_Pred(*_First1, *_First2))            ++_First1;        else            {    // advance both            ++_First1;            ++_First2;            }    return (_First2 == _Last2);    }template<class _InIt1,    class _InIt2,    class _Pr> inline    bool includes(_InIt1 _First1, _InIt1 _Last1,        _InIt2 _First2, _InIt2 _Last2, _Pr _Pred)    {    // test if set [_First1, _Last1) in [_First2, _Last2), using _Pred    _DEBUG_ORDER_PRED(_First1, _Last1, _Pred);    _DEBUG_ORDER_PRED(_First2, _Last2, _Pred);    return (_Includes(_Unchecked(_First1), _Unchecked(_Last1),        _Unchecked(_First2), _Unchecked(_Last2), _Pred));    }        // TEMPLATE FUNCTION includestemplate<class _InIt1,    class _InIt2> inline    bool includes(_InIt1 _First1, _InIt1 _Last1,        _InIt2 _First2, _InIt2 _Last2)    {    // test if all [_First1, _Last1) in [_First2, _Last2), using operator<    return (_STD includes(_First1, _Last1, _First2, _Last2,        less<>()));    }

In The C ++ Standard Library (second edition, 3rd print), it is pointed out that The complexity of this algorithm is at most 2 * (numElems + numSearchElems)-1 comparison.