0522. Longest Uncommon Subsequence II

https://leetcode.com/problems/longest-uncommon-subsequence-ii

Description

Given an array of strings strs, return the length of the longest uncommon subsequence between them. If the longest uncommon subsequence does not exist, return -1.

An uncommon subsequence between an array of strings is a string that is a subsequence of one string but not the others.

A subsequence of a string s is a string that can be obtained after deleting any number of characters from s.

• For example, "abc" is a subsequence of "aebdc" because you can delete the underlined characters in "aebdc" to get "abc". Other subsequences of "aebdc" include "aebdc", "aeb", and "" (empty string).

Example 1:

**Input:** strs = ["aba","cdc","eae"]
**Output:** 3

Example 2:

**Input:** strs = ["aaa","aaa","aa"]
**Output:** -1

Constraints:

• 2 <= strs.length <= 50

• 1 <= strs[i].length <= 10

• strs[i] consists of lowercase English letters.

ac

class Solution {
    public int findLUSlength(String[] strs) {
        // edge cases

        // sort the array in length desc
        // Arrays.sort(strs, (a, b) -> {return b.length() - a.length();});

        // check 
        int max = -1;
        for (int i = 0; i < strs.length; i++) {
            boolean valid = true;
            for (int j = 0; j < strs.length && valid; j++) {
                if (i == j) continue;
                if (isSubsequence(strs[i], strs[j])) valid = false;
            }
            if (valid) max = Math.max(max, strs[i].length());
        }

        return max;
    }

    private boolean isSubsequence(String s1, String s2) {
        int i1 = 0, i2 = 0;
        while (i1 < s1.length() && i2 < s2.length()) {
            if (s1.charAt(i1) == s2.charAt(i2)) {
                i1++;
            }
            i2++;
        }
        return i1 == s1.length();
    }
}
/*
for each string, check if it is subsequence of previous string, if yes continue to check next one.
*/