Leetcode 1208 - Get Equal Substrings Within Budget

Prompt: You are given two strings s and t of the same length. You want to change s to t. Changing the i-th character of s to i-th character of t costs abs(s[i] - t[i]) that is, the absolute difference between the ASCII values of the characters.

You are also given an integer maxCost.

Return the maximum length of a substring of s that can be changed to be the same as the corresponding substring of t with a cost less than or equal to maxCost.

If there is no substring from s that can be changed to its corresponding substring from t, return 0.

Example:

Input: s = "abcd", t = "bcdf", maxCost = 3
Output: 3
Explanation: "abc" of s can change to "bcd". That costs 3, so the maximum length is 3.

Input: s = "abcd", t = "cdef", maxCost = 3
Output: 1
Explanation: Each character in s costs 2 to change to charactor in t, so the maximum length is 1.

Input: s = "abcd", t = "acde", maxCost = 0
Output: 1
Explanation: You can't make any change, so the maximum length is 1.

Solution: We can solve this with a sliding window. The sliding window has a condition where the cost of the current substring in the sliding window is less than the max cost. The runtime of this solution is O(n).