[Leetcode] Repeated DNA Sequences
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"].
大神的代码： http://blog.csdn.net/wzy_1988/article/details/44224749
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Native method:
1 public class Solution { 2 public List<String> findRepeatedDnaSequences(String s) { 3 List<String> res = new ArrayList<>(); 4 if(s == null || s.length() < 2) 5 return res; 6 HashMap<String, Integer> hm = new HashMap<>(); 7 for(int i = 0; i < s.length() - 9; ++i) { 8 String temp = s.substring(i, i + 10); 9 if(hm.containsKey(temp)) 10 hm.put(temp, hm.get(temp) + 1); 11 else 12 hm.put(temp, 1); 13 } 14 for(Map.Entry<String, Integer> entry: hm.entrySet()) { 15 if(entry.getValue() > 1) 16 res.add(entry.getKey()); 17 } 18 return res; 19 } 20 }
但是这种写法浪费了太多的空间。
－－－－－－－－－－－－－－－－－－－－－－－－－－－
Method 2: 利用二进制， 存储整数。
