LeetCode interview Qustions: Anagrams

http://www.leetcode.com/onlinejudge

class Solution {
public:
    vector<string> anagrams(vector<string> &strs) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        multimap<string,string> map;
        for(int i=0;i<strs.size();i++) {
            if(strs[i].length()>0){
                string value = strs[i];
                sort(strs[i].begin(),strs[i].end()); //string也有begin(),end()方法
                map.insert(pair<string,string>(strs[i], value));
            }
        }
        
        vector<string> result;
        if(map.empty()) {
            return result;
        }
        
        multimap<string,string>::iterator it=map.begin();
        string lastkey = it->first;
        string lastvalue=it->second;
        
        for(it++;it!=map.end();) {
            if(it->first == lastkey) {
                result.push_back(lastvalue);
                while(it!=map.end() && it->first == lastkey)
                {
                    result.push_back(it->second);
                    it++;
                }
            }
            else {
                lastkey = it->first;
                lastvalue=it->second;
                it++;
            }
        }
        return result;
    }
};