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/**

* 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 separated by a single space.

*/

public class WordPattern290 {

public boolean wordPattern(String pattern, String str) {

String[] words = str.trim().split("\\s+");

if (pattern.length() != words.length) return false;

Map<Character, String> map = new HashMap<>();

int N = pattern.length();

for (int i=0; i<N; i++) {

String w = words[i];

Character ch = pattern.charAt(i);

if (map.containsKey(ch)) {

if (!map.get(ch).equals(w)) return false;

} else {

if (map.values().contains(w)) return false;

map.put(ch, w);

}

}

return true;

}

public boolean wordPattern2(String pattern, String str) {

String[] words = str.trim().split("\\s+");

if (pattern.length() != words.length) return false;

String[] map = new String[26];

int N = pattern.length();

for (int i=0; i<N; i++) {

String w = words[i];

char ch = pattern.charAt(i);

int idx = ch - 'a';

if (map[idx] != null) {

if (!map[idx].equals(w)) return false;

} else {

if (contains(map, w)) return false;

map[idx] = w;

}

}

return true;

}

private boolean contains(String[] map, String w) {

for (String m: map) {

if (m != null && m.equals(w)) {

return true;

}

}

return false;

}

public boolean wordPattern3(String pattern, String str) {

String[] words = str.trim().split("\\s+");

if (pattern.length() != words.length) return false;

String[] map = new String[26];

Set<String> set = new HashSet<>();

int N = pattern.length();

for (int i=0; i<N; i++) {

String w = words[i];

char ch = pattern.charAt(i);

int idx = ch - 'a';

if (map[idx] != null) {

if (!map[idx].equals(w)) return false;

} else {

if (set.contains(w)) return false;

map[idx] = w;

set.add(w);

}

}

return true;

}

/**

* https://leetcode.com/problems/word-pattern/discuss/73402/8-lines-simple-Java

*/

public boolean wordPattern4(String pattern, String str) {

String[] words = str.split(" ");

if (words.length != pattern.length())

return false;

Map index = new HashMap();

for (Integer i=0; i<words.length; ++i)

if (index.put(pattern.charAt(i), i) != index.put(words[i], i))

return false;

return true;

}

}