Increment the frequency of the triplet
if ( freq . has ( A [ i ] * A [ j ] * A [ k ] ) ) { freq . set ( freq . get ( A [ i ] * A [ j ] * A [ k ] ) , freq . get ( [ A [ i ] * A [ j ] * A [ k ] ] ) + 1 ) ; } else { freq . set ( A [ i ] * A [ j ] * A [ k ] , 1 ) ; } } } }