Given the condition: $T(O(1)) = O(1)$ and $T(n) leq sqrt{n}T(sqrt{n}) + n$. I need to solve this recurrence relation. The hardest part for me is the number of subproblems $sqrt{n}$ is not a constant, it’s really difficult to apply tree method and master theorem here. Any hint? My thought is that let $c = sqrt{n}$ such that $c^2 = n$ so we have $T(c^2) leq cT(c) + c^2$ but I does not look good.