leetcode Anagrams Group(迴文構詞 分組)
阿新 • • 發佈:2019-01-22
題目連結:https://leetcode.com/problems/anagrams/
題意:
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: All inputs will be in lower-case.
分析:Anagram(迴文構詞法)是指打亂字母順序從而得到新的單詞,比如“dormitory”打亂字母吮吸會變成"dirty room","tea"會變成"eat"。
迴文構詞法有一個特點:單詞裡的字母的種類和數目沒有改變,只是改變了字母的排列順序。因此,將幾個單詞按照字母順序排列後,若它們相等,則它們屬於同一組anagrams。
程式碼:
class Solution { public: vector<vector<string>> groupAnagrams(vector<string>& strs) { unordered_map<string,vector<string>> group; for(const auto &s:strs){ string key = s; sort(key.begin(),key.end()); group[key].push_back(s); } vector<vector<string>> res; for(auto it = group.cbegin();it!=group.cend();it++){ vector<string> tmp; tmp.insert(tmp.end(),it->second.begin(),it->second.end()); res.push_back(tmp); } return res; } };