題目
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:
pattern = "abba", str = "dog cat cat dog" should return true.
pattern = "abba", str = "dog cat cat fish" should return false.
pattern = "aaaa", str = "dog cat cat dog" should return false.
pattern = "abba", str = "dog dog dog dog" should return false.
答案
class Solution {
public boolean wordPattern(String pattern, String str) {
String[] words = str.split(" ");
if(words.length != pattern.length()) return false;
Map<Character, String> map = new HashMap<>();
Map<String, Character> map2 = new HashMap<>();
for(int i = 0; i < pattern.length(); i++) {
char p = pattern.charAt(i);
String w = map.get(p);
if(w == null) {
if(map2.get(words[i]) != null) return false;
map.put(p, words[i]);
map2.put(words[i], p);
}
else {
if(!w.equals(words[i])) return false;
}
}
return true;
}
}
