Comparing the efficiecy of 2 run times
$\log(n)-k$ is const $\implies$ $2^{\log(n)-k}$ is const $\implies O(2^{k} \cdot \log(n)) = O(2^{\log(n)-k} \cdot 2^{k} \cdot \log(n)) = O(2^{\log(n)} \cdot \log(n)) = O(n \cdot \log(n))$