Given a pattern and a string str, find if str follows the same pattern.
Here follow means a full match, such that there is a bijection between a letter in pattern and a non-empty word in str.
Examples:
"abba", str = "dog cat cat dog" should return true."abba", str = "dog cat cat fish" should return false."aaaa", str = "dog cat cat dog" should return false."abba", str = "dog dog dog dog" should return false.
Notes:
You may assume pattern contains only lowercase letters, and str contains lowercase letters separated by a single space.
Credits:
Special thanks to @minglotus6 for adding this problem and creating all test cases.
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1 public class Solution { 2 public boolean wordPattern(String pattern, String str) { 3 HashMap<Character, String> hm = new HashMap<Character, String>(); 4 Set<String> set = new HashSet<String>(); 5 String[] arr = str.split(" "); 6 if(arr.length != pattern.length()) return false; 7 for(int i =0 ;i< pattern.length();i++){ 8 if(hm.get(pattern.charAt(i)) != null){ 9 if(!hm.get(pattern.charAt(i)).equals(arr[i])) return false; 10 }else{ 11 if(set.contains(arr[i])) return false; 12 else{ 13 hm.put(pattern.charAt(i),arr[i]); 14 set.add(arr[i]); 15 } 16 } 17 } 18 return true; 19 20 } 21 }
290. Word Pattern java solutions
原文：http://www.cnblogs.com/guoguolan/p/5487143.html