Repeated DNA Sequences

1. Title

Repeated DNA Sequences

2.   Http address

https://leetcode.com/problems/repeated-dna-sequences/

3. The question

All DNA is composed of a series of nucleotides abbreviated as A, C, G, and T, for example: "ACGAATTCCG". When studying DNA, it is sometimes useful to identify repeated sequences within the DNA.

Write a function to find all the 10-letter-long sequences (substrings) that occur more than once in a DNA molecule.

For example,

Given s = "AAAAACCCCCAAAAACCCCCCAAAAAGGGTTT",

Return:
["AAAAACCCCC", "CCCCCAAAAA"].

4. My code (AC)

    //Accept
    public static List<String> findRepeatedDNASeq(String s){

        List<String> re = new ArrayList<String>();
        Map<String,Integer> dit = new HashMap<String,Integer>();
        String key = "";
        int value = 0;
        if ( s == null || s.length() < 10 )
        {
            return re;
        }

        for(int i = 0 ; i <= s.length() - 10;i++ )
        {
                key = s.substring(i,i+10);
                if( dit.containsKey(key) )
                {
//                    i += 10;
                    value = dit.get(key);
                    if( value == 1 )
                    {
                        re.add(key);
                        dit.put(key,0);
                    }

                }else{
                    dit.put(key,1);
                }
        }
        
        return re;
    }