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.
Example 1:
Input: pattern ="abba", str ="dog cat cat dog"Output: true
Example 2:
Input:pattern ="abba", str ="dog cat cat fish"Output: false
Example 3:
Input: pattern ="aaaa", str ="dog cat cat dog"Output: false
Example 4:
Input: pattern ="abba", str ="dog dog dog dog"Output: false
Notes:
You may assume pattern contains only lowercase letters, and str contains lowercase letters that may be separated by a single space.
class Solution { public boolean wordPattern(String pattern, String str) { String[] words = str.split(" "); if (words.length != pattern.length()) return false; final Map<Character, String> map1 = new HashMap<>(); final Map<String, Character> map2 = new HashMap<>(); for (int i = 0; i < words.length; ++i) { Character key1 = pattern.charAt(i); if (map1.containsKey(key1)) { String value = map1.get(key1); if (!value.equals(words[i])) return false; } else { map1.put(key1, words[i]); } final String key2 = words[i]; if (map2.containsKey(key2)) { char value = map2.get(key2); if (value != pattern.charAt(i)) return false; } else { map2.put(key2, pattern.charAt(i)); } } return true; } }
和Isomorphic Strings很类似，用两个HashMap, 记录从字符到字符串和字符串到字符的映射。
原文：https://www.cnblogs.com/wentiliangkaihua/p/11406769.html