Problem Description

You are given a string s and an integer k. You can choose any character of the string and change it to any other uppercase English character. You can perform this operation at most k times.

Return the length of the longest substring containing the same letter you can get after performing the above operations.

Examples

Example 1:

Input: s = "ABAB", k = 2
Output: 4
Explanation: Replace the two 'A's with two 'B's or vice versa.

Example 2:

Input: s = "AABABBA", k = 1
Output: 4
Explanation: Replace the one 'A' in the middle with 'B' and form "AABBBBA".
The substring "BBBB" has the longest repeating letters, which is 4.

Constraints:

• 1 <= s.length <= 105
• s consists of only uppercase English letters.
• 0 <= k <= s.length

解析

給定一個字串 s, 還有一個非負整數 k

其中每個 s[i] 都是大寫英文字母

要求寫一個演算法字串 s 中在可以允許更換 k 次字元的情況下，找出最長的字元不重複字元的子字串長度

要找出不重複字元的最長子字串，相當於是要是找出出現最多次的字元並且每個字元位置必須相連