if ( _one . first == 0 ) see point 2
_one . second = ( _one . second + 1 ) % size2 ; } } else if ( a1 [ _one . first ] + a2 [ _one . second ] > a2 [ _two . first ] + a1 [ _two . second ] ) { if ( a2 [ _two . first ] < a1 [ _two . second ] ) { cout << " [ " << a2 [ _two . first ] << " , ▁ " << a1 [ _two . second ] << " ] ▁ " ;