/**

* Question Link: https://leetcode.com/problems/word-pattern/

* Primary idea: Use two dictionarys to determine if a character is unique to a word

* Time Complexity: O(n), Space Complexity: O(n)

*/

class WordPattern {

func wordPattern(pattern: String, _ str: String) -> Bool {

var wordDict = [String: Character]()

var charDict = [Character: String]()

let strs = str.characters.split{$0 == " "}.map(String.init)

let patterns = [Character](pattern.characters)

guard patterns.count == strs.count else {

return false

}

for i in 0 ..< strs.count {

let currentWord = strs[i]

let currentChar = patterns[i]

if wordDict[currentWord] == nil && charDict[currentChar] == nil{

wordDict[currentWord] = currentChar

charDict[currentChar] = currentWord

} else {

if wordDict[currentWord] != currentChar {

return false

}

}

}

return true

}