(void) setOptimalTone:(int)minTone :(int)maxTone
{
    static const int kDiapason = 12; // 1 octave == 12 semitone

    int cnt = maxTone - minTone + 1 - (kDiapason - 1);
    if( cnt > 1 )
    {
        int *tones = (int*)malloc(sizeof(int)*cnt);
        memset(tones, 0, sizeof(int)*cnt);

        for(int g=0, h=minTone; g < cnt; ++h, ++g)
        {
            for(int i=0; i < _lines.countLines; ++i)
            {
                for(int m=0; m < _lines.line[i].countNotes; ++m)
                {
                    int tone = _lines.line[i].note[m].tone;
                    if( tone >= h && tone < h+kDiapason )
                    {
                        ++tones[g];
                    }
                }
            }
        }

        int idxDiapason = 0;
        int optimalDiapason = 0;
        for(int i=0; i < cnt; ++i)
        {
            if( optimalDiapason < tones[i] )
            {
                optimalDiapason = tones[i];
                idxDiapason = i;
            }
        }
        free(tones);

        _lines.optimalMinTone = idxDiapason + minTone;
        _lines.optimalMaxTone = idxDiapason + minTone + kDiapason - 1;
    }
    else
    {
        BOOL b = NO;
        while(maxTone - minTone + 1  < kDiapason)
        {
            b = !b;
            b ?  ++maxTone : --minTone;
        }
        _lines.optimalMinTone = minTone;
        _lines.optimalMaxTone = maxTone;
    }
    //----------------------------------------------------------------------
    for(int i=0; i < _lines.countLines; ++i)
    {
        for(int m=0; m < _lines.line[i].countNotes; ++m)
        {
            if(_lines.line[i].note[m].tone > _lines.optimalMaxTone)
                _lines.line[i].note[m].tone = _lines.optimalMaxTone;
            if(_lines.line[i].note[m].tone < _lines.optimalMinTone)
                _lines.line[i].note[m].tone = _lines.optimalMinTone;
        }
    }

}