290. Word Pattern

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 inpattern and a non-empty word in str.

Examples:

1. pattern = "abba", str = "dog cat cat dog" should return true.
2. pattern = "abba", str = "dog cat cat fish" should return false.
3. pattern = "aaaa", str = "dog cat cat dog" should return false.
4. pattern = "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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Solution:

Tips:

seems to 205. Isomorphic Strings

Java Code:

public class Solution {    public boolean wordPattern(String pattern, String str) {        char[] p = pattern.toCharArray();        String[] s = str.split(" ");        if (p == null && s == null) {            return true;        }        if (p == null && s != null || p != null && s == null || p.length != s.length){            return false;        }                int[] pTable = new int[256];        Map<String, Integer> sTable = new HashMap<>();        for (int i = 0; i < s.length; i++) {            sTable.put(s[i], 0);        }                for (int i = 0; i < p.length; i++) {            if (!sTable.containsKey(s[i]) || (pTable[p[i]] != sTable.get(s[i]))) {                return false;            }            pTable[p[i]] = i + 1;            sTable.put(s[i], i + 1);        }        return true;    }}