How to Solve Largest Merge Of Two Strings Problem

You are given two strings word1 and word2. You want to construct a string merge in the following way: while either word1 or word2 are non-empty, choose one of the following options: If word1 is non-empty, append the first character in word1 to merge and delete it from word1. For example, if word1 = "abc" and merge = "dv", then after choosing this operation, word1 = "bc" and merge = "dva". If word2 is non-empty, append the first character in word2 to merge and delete it from word2. For example, if word2 = "abc" and merge = "", then after choosing this operation, word2 = "bc" and merge = "a". Return the lexicographically largest merge you can construct. A string a is lexicographically larger than a string b (of the same length) if in the first position where a and b differ, a has a character strictly larger than the corresponding character in b. For example, "abcd" is lexicographically larger than "abcc" because the first position they differ is at the fourth character, and d is greater than c.