If last index is reached , then return the highest ( positive ) and lowest ( negative ) values
if ( index + 1 == List . length ) { if ( lowest < 0 && highest >= 0 ) { return ( [ highest , lowest ] ) ; } else if ( lowest <= 0 && highest <= 0 ) { return ( [ Number . MIN_VALUE , lowest ] ) ; } else if ( lowest >= 0 && highest >= 0 ) { return ( [ highest , Number . MIN_VALUE ] ) ; } }