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# LeetCode 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 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.

This problem is similar to 205. Isomorphic String. The difference is problem 205 we compare two strings but this problem we compare a pattern string with a string built with different words. This time we map pattern string to a new string and map str to a new string too.

First, we create a function to map string array to a new string.

Then we can split pattern string and words string to string arrays, then map then to two new string, compare them:

To see more hashtable related problems, see
Problems and Solutions of Hashmap.

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