Leetcode #320. Generalized Abbreviation

[yokostan]

https://leetcode.com/problems/generalized-abbreviation/discuss/77190/Java-backtracking-solution

class Solution {
    public List<String> generateAbbreviations(String word) {
        List<String> res = new ArrayList<>();
        helper(res, word, 0, "", 0);
        return res;
    }

    private void helper(List<String> res, String word, int pos, String cur, int count) {
        if (pos == word.length()) {
            if (count > 0) cur += count;
            res.add(cur);
        }
        else {
            helper(res, word, pos + 1, cur, count + 1);
            helper(res, word, pos + 1, cur + (count > 0 ? count : "") + word.charAt(pos), 0);
        }
    }
}

We can divide the case to 'abbreviate it' or 'omit it'.