How to compare computational complexity of algorithms I have three different algorithms for achieving a target. Algorithm 1 takes $O(Mn)$ - $M$ is constsnt and n is variable,Algorithm 2 takes $O(min(p^3,n^3))$ - both $p$ and $n$ is variable and Algorithm 3 takes $O(nk+nd)$ - $k$ constant, $n$ and $d$ is variable. Is it possible to compare these algorithms? Which algorithm is fast and how much fast than other two algorithms?
Since you have three different variable it is not easy to compare their running times. For example if $d = 1/n$ then $nd = 1$. But if $d = n$ then $nd$ is $n^2$. If $d$ and $n$ are unrelated to each other asymptotically or functionally I think you may not compare them. Analogously for $p$.

Update:
If $M,p,k$ and $d$ are constant then we have Alg1 is $O(n)$, Alg2 is $O(min(p^3, n^3)) = O(p^3) = O(1)$, and Alg3 is $O(n)$.