Substrings of length k with k-1 distinct elements
Medium Accuracy: 61.82% Submissions: 1172 Points: 4

Given a String S and an integer K. Find the count of all substrings of length K which have exactly K-1 distinct characters.

 

Example 1:

Input:
S = "abcc"
K = 2
Output:
1
Explanation:
Possible substrings of length K = 2 are
ab : 2 distinct characters
bc : 2 distinct characters
cc : 1 distinct character
Only one valid substring exists {"cc"}. 
Example 2:
Input:
S = "aabab"
K = 3
Output :
3
Explanation:
Possible substrings of length K = 3 are
aab : 2 distinct characters
aba : 2 distinct characters
bab : 2 distinct characters.
All of these Substrings are a possible answer,
so the count is 3.


Your Task:  
You don't need to read input or print anything. Your task is to complete the function countOfSubstrings() which takes a String S and an integer K as input and returns the count of substrings of length K having K-1 distinct characters.


Expected Time Complexity: O(|S|)
Expected Auxiliary Space: O(constant)


Constraints:
1 ≤ K ≤ |S| ≤ 105

We are replacing the old Disqus forum with the new Discussions section given below.
Click here to view old Disqus comments.


to report an issue on this page.

Editorial

We strongly recommend solving this problem on your own before viewing its editorial. Do you still want to view the editorial?

Yes

All Submissions

My Submissions:

Login to access your submissions.

Substrings of length k with k-1 distinct elements

Output Window