else update as necessary ( point 1 )
else if ( a1 [ _one . first ] + a2 [ _one . second ] <= a2 [ _two . first ] + a1 [ _two . second ] ) { if ( a1 [ _one . first ] < a2 [ _one . second ] ) { cout << " [ " << a1 [ _one . first ] << " , ▁ " << a2 [ _one . second ] << " ] ▁ " ;