LeetCode187—Repeated DNA Sequences

原题

原题链接

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”].

---

分析

重复出现的子串，长度为10。
用一个hash来保存，最后结果去重即可。

class Solution{     public:    vector<string> findRepeatedDnaSequences(string s)    {         vector<string>result;        unordered_set<string>visited;        for(int i=0;i+10<=s.size();++i)        {            string tmp(s.begin()+i,s.begin()+i+10);            if(visited.end()==visited.find(tmp))            {                visited.insert(tmp);            }            else                result.push_back(tmp);        }        //去重        result.erase(unique(result.begin(),result.end()),result.end());        //打印       // ostream_iterator<string> out_it(cout,"\n");       // copy(result.begin(),result.end(),out_it);        return result;    } };