Sort and merge string lists by length

Given two unsorted lists of strings, return a single list sorted by ascending string length. Specify your tie-breaking rule for equal-length strings (e.g., preserve original relative order for stability). Analyze time and space complexity and whether your sort is stable. Follow-up: If each input list is already individually sorted by length with the same tie-breaker, design and implement an efficient merge to produce a globally length-sorted list. Discuss in-place versus extra-memory approaches and their complexities.