Substring XOR Queries

Given a binary string s and many queries [first, second], for each query find the shortest substring whose integer value val satisfies val ^ first == second (returning its [left,right] or [-1,-1]). Key insight: since values ≤ 1e9, relevant substring lengths are bounded (≈30), so you can preprocess integer values of short substrings and answer queries by looking up target = first ^ second.