Problem - Range Frequency Query

Design a data structure for an array.

Answer queries: "How many times does value $v$ appear in $A[l..r]$?" Example: $A = [12, 33, 4, 56, 22, 2, 34, 33, 22, 12, 34, 56]$ Query $(1, 10, 33)$ returns $2$ (indices 1 and 7).

You're solving the frequency counting problem that wavelet trees handle efficiently. Constraints: up to $10^5$ elements, up to $10^5$ queries.