https://www.cnblogs.com/grandyang/p/6014408.html
用两个hash表来存储个数
class Solution { public: vector<int> findAnagrams(string s, string p) { vector<int> result; if(s.empty()) return result; vector<int> container1(256,0); vector<int> container2(256,0); for(int i = 0;i < p.length();i++){ container1[s[i]]++; container2[p[i]]++; } if(container1 == container2) result.push_back(0); for(int i = p.length();i < s.length();i++){ container1[s[i - p.length()]]--; container1[s[i]]++; if(container1 == container2) result.push_back(i - p.length() + 1); } return result; } };