Count Of Substrings With Exactly K Unique Characters
medium
1. You are given a string(str) and a number K. 2. You have to find the count of valid substrings of the given string. 3. Valid substring is defined as a substring that has exactly K unique characters.
Constraints
1 <= length of string <= 10^5 1 <= k <= 26
Format
Input
A string
Output
A number representing count of substrings with exactly K unique characters.
Example
Sample Input
aabcbcdbca
2
Sample Output
12
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