Sanket and strings

#1

I am stuck on the approach to this question and i am not getting the editorial explanation as well. Pls Explain

#2

@sukh28 hey sukhnandan
Sanket has a string consisting of only a and b as the characters. Sanket describes perfectness of a string as the maximum length substring of equal characters. Sanket is given a number K which denotes the maximum number of characters he can change. Find the maximum perfectness he can generate by swapping no more than k characters.

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.

the dry run of the above code is in the link sanket and strings

Let the first pointer is l and the second pointer is r. Then for every position l we will move right end r until on the substring si.si + 1… sr it is possible to make no more than k swaps to make this substring beautiful. Then we need to update the answer with length of this substring and move l to the right.
let try with this do come with a code next if you will fail I will help you with coding part.

#3

i understood the question but i am still stuck with how to approach it. and i could not understand the explanation in your last paragraph, pls elaborate on that.

#4

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