What is wrong in this code.. It is failing all test cases

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hello @ayush.18
ur logic is not correct.

Basically, there is a string which consists of only a and b. A substring is a contiguous sequence of characters within a string. Our aim is to generate substrings of a and b by swapping characters such that the lengths of substrings of either a or b is maximum possible. The only constraint we have here is that only k swaps are allowed. So, you have to tell the maximum possible length of the substrings that can be generated. By swapping, we mean that a can be replaced by b and b can be replaced by a.

For example:
Consider the following string: abba and k = 2
So, we can make only two swaps

abba (swaps = 0)
aaba (swaps = 1)
aaaa (swaps = 2)

Thus, the maximum length of substring is 4.

Consider the string: ababab and k=2

ababab (swaps = 0)
aaabab (swaps =1)
aaaaab (swaps = 2)

Thus, the maximum length of substring is 5.

approach->
You can solve this problem in O(n) time using the two pointer approach.

  • Make two variabes , say i and j .
  • i defines the beginning of a window and j defines its end.
  • Start i from 0 and j from k.
  • Let’s talk about the singular case when we are considering the max window for only 'a’s and consider only the swapping of b-> a. If we are able to get the answer for max window of consecutive 'a’s , we can simply implement the same algo for the max ‘b’ window as well.
  • So we started i from 0 and j from k.
  • Move j ahead freely as long as there are ‘a’ characters at s[ j ] position.
  • Maintain a count variable which counts the number of swaps made or the number of 'b’s in our A window.
  • If you encounter a ‘b’ char at s[ j ] position , increment the count variable. Count should never exceed k .
  • Take the size of the window at every point using length = j - i + 1;
  • Compute the max size window this way and do the same for ‘b’ as well.
  • Output the maximum size window of ‘a’ and ‘b’.