没看懂的是,2 height的N=2^n or (2k)^n, if the former, 1 is also sufficient 在看小熊机井12月2日,X is a positive integer. 2-height of X is defined as the greatest negative integer n where 2^n is a factor of X. X既然已经是Positive, how can 2-height of x changed to be greatest negative interger. the sentense is somewhat convoluted. No indication shows that it is exponent as 2^n.