leetcode——49——Group Anagrams

Given an array of strings, group anagrams together.

For example, given:

["eat", "tea", "tan", "ate", "nat", "bat"]

,

Return:

[
["ate", "eat","tea"],
["nat","tan"],
["bat"]
]

Note:

For the return value, each inner list's elements must follow the lexicographic order.
All inputs will be in lower-case.

class Solution {
public:
vector<vector<string>> groupAnagrams(vector<string>& strs) {
if (strs.empty())
return vector<vector<string> >();

int len = strs.size();

//将字符串数组按照字典顺序排序
sort(strs.begin(), strs.end());

//存储结果
vector<vector<string> > ret;

//利用哈希思想构建map，将排序后相等的字符串存在相应的vector
map<string, vector<string>> mv;

for (int i = 0; i < len; i++)
{
string str = strs[i];
sort(str.begin(), str.end());

mv[str].push_back(strs[i]);
}

for (map<string, vector<string> >::iterator iter = mv.begin(); iter != mv.end(); iter++)
ret.push_back(iter->second);

return ret;

}
};