Check if y can act as the middle element of triplet with the given solution of 1 / a + 1 / b + 1 / c = 1
if ( s % test [ j ] [ 0 ] != 0 ) continue ; if ( s % test [ j ] [ 2 ] != 0 ) continue ; int x = s / test [ j ] [ 0 ] ; ll z = s / test [ j ] [ 2 ] ; if ( x > MAX z > MAX ) continue ; int l = 0 ; int r = indices [ x ] . size ( ) - 1 ; int first = -1 ;