Programming Interview Question — Longest String Chain

Lintcode 257 or Leetcode 1048

Question setup

Given a list of words, each word consists of English lowercase letters.
Let’s say word1 is a predecessor of word2 if and only if we can add exactly one letter anywhere in word1 to make it equal to word2. For example, “abc” is a predecessor of “abac”.
A word chain is a sequence of words [word_1, word_2, …, word_k] with k >= 1, where word_1 is a predecessor of word_2, word_2 is a predecessor of word_3, and so on.
Return the longest possible length of a word chain…