private int getVal(char ch) {
        switch(ch) {
            case 'A':
                return 0;
            case 'C':
                return 1;
            case 'G':
                return 2;
            case 'T':
                return 3;
            default:
                throw new IllegalArgumentException();
        }
    }
Date 03/08/2016
@author Tushar Roy

Find repeated sequence of length 10 in string consisting of A,C,G,T

Time complexity is O(n)
Space complexity is O(n)

https://leetcode.com/problems/repeated-dna-sequences/
src/com/interview/bits/RepeatedDnaSequence.java