In general if we consider an arbitrary number of pushes n + 1 to an array of size n, we notice that push operations take constant time except for the last one which takes Θ ( n ) {\displaystyle \Theta (n)} time to perform the size doubling operation. Since there were n + 1 operations total we can take the average of this and find that pushing elements onto the dynamic array takes: n Θ ( 1 ) + Θ ( n ) n + 1 = Θ ( 1 ) {\displaystyle {\tfrac {n\Theta (1)+\Theta (n)}{n+1}}=\Theta (1)} , constant time.[1]