Problem - Range Sum Queries I

You're given an array of $n$ integers and $q$ queries. Each query is either:

$1.$ Update: set $arr[i] = v$

$2.$ Query: return $sum(l, r)$ Constraints: $n, q \leq 2 \cdot 10^5$. You're solving the classic problem for sqrt decomposition. Before reading the solution, think about whether segment trees or sqrt decomposition would be better here. What's the tradeoff?