LeetCode/290_Word_Pattern at master · KnowledgeCenterYoutube/LeetCode · GitHub

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Leetcode 290: Word Pattern
Detailed video explanation: https://youtu.be/cwBUZKqH6sw
==========================================


C++:
----
class Solution {
public:
    bool wordPattern(string pattern, string str) {
        unordered_map<char, string> char_map;
        unordered_map<string, char> word_map;

        stringstream s(str);
        string word;
        int n = pattern.size(), i = 0;

        while(s >> word){
            if(i == n) return false;
            char c = pattern[i];
            if(char_map.count(c) != word_map.count(word)) return false;
            if(char_map.count(c)){
                if( (word_map[word] != c) || (char_map[c] != word)) return false;
            } else {
                char_map.insert({c, word});
                word_map.insert({word, c});
            }
            i++;
        }
        return i == n;
    }
};


Java:
-----
class Solution {
    public boolean wordPattern(String pattern, String str) {
        Map<Character, String> char_map = new HashMap();
        Map<String, Character> word_map = new HashMap();

        int n = pattern.length(), i = 0;
        String[] words = str.split(" ");
        if(n != words.length) return false;

        while(i < n){
            char c = pattern.charAt(i);
            String word = words[i];
            if(char_map.containsKey(c) != word_map.containsKey(word)) return false;
            if(char_map.containsKey(c)){
                if( (word_map.get(word) != c) || !(char_map.get(c).equals(word)) ) return false;
            } else {
                char_map.put(c, word);
                word_map.put(word, c);
            }
            i++;
        }
        return i == n;
    }
}


Python3:
--------
class Solution:
    def wordPattern(self, pattern: str, str: str) -> bool:
        char_map, word_map = {}, {}
        n, i = len(pattern), 0
        words = str.split(" ")
        if n != len(words): return False

        while i < n:
            c, word = pattern[i], words[i]
            if (c in char_map) != (word in word_map): return False
            if c in char_map:
                if (word_map[word] != c) or (char_map[c] != word): return False
            else:
                char_map[c] = word
                word_map[word] = c
            i += 1
        return i == n