There is a malfunctioning keyboard where some letter keys do not work. All other keys on the keyboard work properly.

Given a string text of words separated by a single space (no leading or trailing spaces) and a string brokenLetters of all distinct letter keys that are broken, return the number of words in text you can fully type using this keyboard.

Example 1:

Input: text = "hello world", brokenLetters = "ad"
Output: 1
Explanation: We cannot type "world" because the 'd' key is broken.


Example 2:

Input: text = "leet code", brokenLetters = "lt"
Output: 1
Explanation: We cannot type "leet" because the 'l' and 't' keys are broken.


Example 3:

Input: text = "leet code", brokenLetters = "e"
Output: 0
Explanation: We cannot type either word because the 'e' key is broken.


Constraints:

• 1 <= text.length <= 104
• 0 <= brokenLetters.length <= 26
• text consists of words separated by a single space without any leading or trailing spaces.
• Each word only consists of lowercase English letters.
• brokenLetters consists of distinct lowercase English letters.

## Solution: Hashset / bitset

Time complexity: O(n)
Space complexity: O(1)

## C++

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