题目链接: https://leetcode.com/problems/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"].
思路: 一个简单的hash表就可以搞定, 居然这么简单就过了, 也有点太水了吧.
代码如下:
class Solution { public: vector<string> findRepeatedDnaSequences(string s) { if(s.size() < 10) return {}; for(int i =0; i<= s.size()-10; i++) { string str = s.substr(i, 10); hash[str]++; if(hash[str] == 2) result.push_back(str); } return result; } private: unordered_map<string, int> hash; vector<string> result; };