LeetCode 187. 重复的DNA序列(Repeated DNA Sequences)

187. 重复的DNA序列

187. Repeated DNA Sequences

题目描述

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.

LeetCode187. Repeated DNA Sequences中等

Example:

Input: s = "AAAAACCCCCAAAAACCCCCCAAAAAGGGTTT"

Output: ["AAAAACCCCC", "CCCCCAAAAA"]

Java 实现

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

class Solution {
    public List<String> findRepeatedDnaSequences(String s) {
        Set<String> set = new HashSet<>();
        Set<String> repeat = new HashSet<>();
        for (int i = 0; i + 9 < s.length(); i++) {
            String str = s.substring(i, i + 10);
            if (!set.add(str)) {
                repeat.add(str);
            }
        }
        return new ArrayList<>(repeat);
    }
}

参考资料

• https://www.cnblogs.com/grandyang/p/4284205.html
• https://leetcode.com/problems/repeated-dna-sequences/
• https://leetcode-cn.com/problems/repeated-dna-sequences/