LeetCode - Longest Uncommon Subsequence II

Question Definition

Given a list of strings, you need to find the longest uncommon subsequence among them. The longest uncommon subsequence is defined as the longest subsequence of one of these strings and this subsequence should not be any subsequence of the other strings.

A subsequence is a sequence that can be derived from one sequence by deleting some characters without changing the order of the remaining elements. Trivially, any string is a subsequence of itself and an empty string is a subsequence of any string.

The input will be a list of strings, and the output needs to be the length of the longest uncommon subsequence. If the longest uncommon subsequence doesn’t exist, return -1.

Example 1:

Input: "aba", "cdc", "eae"
Output: 3

Note:

1. All the given strings’ lengths will not exceed 10.
2. The length of the given list will be in the range of [2, 50].

   Java Solution

   ```java public int findLUSlength(String[] strs) { Map<String, Integer> subseqFreq = new HashMap<>(); for (String s : strs) for (String subSeq : getSubseqs(s)) subseqFreq.put(subSeq, subseqFreq.getOrDefault(subSeq, 0) + 1); int longest = -1; for (Map.Entry<String, Integer> entry : subseqFreq.entrySet()) if (entry.getValue() == 1) longest = Math.max(longest, entry.getKey().length()); return longest; }

public static Set getSubseqs(String s) { Set res = new HashSet<>(); if (s.length() == 0) { res.add(""); return res; } Set subRes = getSubseqs(s.substring(1)); res.addAll(subRes); for (String seq : subRes) res.add(s.charAt(0) + seq); return res; } ```