[LeetCode][JavaScript]Word Pattern

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 substring 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.

---

输入的str要匹配pattern的模式。

需要开两个哈希表，一个是pattern和str的映射，还有一个记录pattern有没有用过。

/**
 * @param {string} pattern
 * @param {string} str
 * @return {boolean}
 */
var wordPattern = function(pattern, str) {
    var dict = {}, used = {};
    var strArr = str.split(' ');
    if(pattern.length !== strArr.length){
        return false;
    }
    for(var i = 0; i < strArr.length; i++){
        if(!dict[strArr[i]]){
            if(used[pattern[i]]){
                return false;
            }else{
                used[pattern[i]] = true;
            }
            dict[strArr[i]] = pattern[i];
        }else{
            if(dict[strArr[i]] !== pattern[i]){
                return false;
            }
        }
    }
    return true;
};