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Leetcode290-wordPattern

Posted on Edited on In Views: Valine:
Solution Report of LeetCode Acceptted

Description

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

Example 1:

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Input: pattern = "abba", str = "dog cat cat dog"
Output: true

Example 2:
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Input:pattern = "abba", str = "dog cat cat fish"
Output: false

Example 3:
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Input: pattern = "aaaa", str = "dog cat cat dog"
Output: false

Example 4:
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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.

Solution

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class Solution {
    public boolean wordPattern(String pattern, String str) {
        HashMap<Character, String> map1 = new HashMap<>();
        HashMap<String, Character> map2 = new HashMap<>();
        String[] dic = str.split(" ");
        if (pattern.length() != dic.length) return false;
        for (int i = 0; i < dic.length; i++){
            char ch = pattern.charAt(i);
            if (!map1.containsKey(ch)){
                map1.put(ch, dic[i]);
                if (!map2.containsKey(dic[i])){
                    map2.put(dic[i], ch);
                }
                else return false;
            }
            else {
                if (!dic[i].equals(map1.get(ch))) return false;
            }
        }
        return true;
    }
}