Watch 10 video solutions for Count the Number of Special Characters II, a medium level problem involving Hash Table, String. This walkthrough by Aryan Mittal has 2,408 views views. Want to try solving it yourself? Practice on FleetCode or read the detailed text solution.
You are given a string word. A letter c is called special if it appears both in lowercase and uppercase in word, and every lowercase occurrence of c appears before the first uppercase occurrence of c.
Return the number of special letters in word.
Example 1:
Input: word = "aaAbcBC"
Output: 3
Explanation:
The special characters are 'a', 'b', and 'c'.
Example 2:
Input: word = "abc"
Output: 0
Explanation:
There are no special characters in word.
Example 3:
Input: word = "AbBCab"
Output: 0
Explanation:
There are no special characters in word.
Constraints:
1 <= word.length <= 2 * 105word consists of only lowercase and uppercase English letters.