# *Josephus problem* $n$ people numbered from 1 to $n$ sit in a circle and play a game. Starting from the first person and every $k$th person is eliminated. Write an algorithm that prints out the order in which people are eliminated.
# *(Level ancestor)* You are given an tree of size $n$. $ancestor(node, levelsUp)$ finds the node’s ancestor that is $levelsUp$ steps up. For example, $ancestor(node, 1)$ returns the father and ancestor(node, 2) returns the grandfather. Implement $ancestor(node, levelsUp)$ efficiently. ($O(sqrt{n})$ per query)

# *(Range median)* You are given an array of size $n$. Implement a data structure to perform update operations $a[i] = k$ and range median operations efficiently. The range median query, $median(l, r)$  returns the median element of the sorted subsequence $a[l..r]$. ($O(\log{n})$ per update and $O(\sqrt{n}\log{n})$ per query)

# *(Range median)* You are given an array of size $n$. Implement a data structure to perform update operations $a[i] = k$ and range median operations efficiently. The range median query, $median(l, r)$  returns the median element of the sorted subsequence $a[l..r]$. $O(\log{n})$ per update and $O(\sqrt{n}\log{n})$ per query

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