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Given a string, we can "shift" each of its letter to its successive letter, for example: "abc" -> "bcd". We can keep "shifting" which forms the sequence:
"abc" -> "bcd" -> ... -> "xyz"
Given a list of strings which contains only lowercase alphabets, group all strings that belong to the same shifting sequence.
For example, given: ["abc", "bcd", "acef", "xyz", "az", "ba", "a", "z"],
Return:
[ ["abc","bcd","xyz"], ["az","ba"], ["acef"], ["a","z"] ]
1 public class Solution { 2 public List<List<String>> groupStrings(String[] strings) { 3 4 List<List<String>> res = new ArrayList<List<String>>(); 5 HashMap<String, List<String>> map = new HashMap<String, List<String>>(); 6 7 for(String word : strings){ 8 String key = ""; 9 int offset = word.charAt(0) - ‘a‘; 10 for(int i = 1; i < word.length(); i++){ 11 key += (word.charAt(i) - offset + 26) % 26; 12 } 13 14 if(!map.containsKey(key)){ 15 map.put(key, new ArrayList<String>()); 16 } 17 map.get(key).add(word); 18 } 19 20 for(List<String> list : map.values()){ 21 Collections.sort(list); 22 res.add(list); 23 } 24 25 return res; 26 27 } 28 }
reference: https://leetcode.com/discuss/67240/around-13-lines-code-in-java
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原文地址：http://www.cnblogs.com/hygeia/p/5074818.html
