Word Pattern II (Round 1, LC 291 :)

Problem Overview

• Decide if string s matches a pattern via a bijective mapping from each pattern char to a non-empty substring; return true/false.
• Input: pattern and s; Output: boolean; Constraints: lengths 1–20, lowercase English letters.
• Domain: string pattern matching and text processing, validating one-to-one mappings.
• From Microsoft interviews (Round 1) and a common coding interview interview question/problem (LC 291, Word Pattern II).