https://leetcode.com/problems/longest-string-chain

Solution.java

class Solution {
    
    private boolean isPred(String a, String b) {
        int diff = 0;
        if(a.length() != b.length()-1) return false;
        for(int i = 0 , j = 0;i<a.length() && j<b.length() ;) {
            if(a.charAt(i) == b.charAt(j)) {
                i++;
                j++;
            } else {
                if(diff>0) return  false;
                diff++;
                j++;
            }
        }
        return true;
    }
    public int longestStrChain(String[] words) {
        int[] dp = new int[words.length];
        Integer max = Integer.MIN_VALUE;
        for(int i = 0;i<dp.length;i++) dp[i]=1;
        Arrays.sort(words, new Comparator<String>() {
            public int compare(String s1, String s2) {
                return s1.length() - s2.length();
            }
        });
        for(int j = 1; j<words.length;j++) {
            for(int i = 0;i<j; i++) {
                if(isPred(words[i], words[j])) {
                    dp[j] = Math.max(dp[j], 1+dp[i]);
                    max = Math.max(max, dp[j]);
                }
            }
        }
        //System.out.println(Arrays.toString(dp));
        return Math.max(1, max);
    }
}