1638. Count Substrings That Differ by One Character

Given two strings s and t, find the number of ways you can choose a non-empty substring of s and replace a single character by a different character such that the resulting substring is a substring of t. In other words, find the number of substrings in s that differ from some substring in t by exactly one character. For example, the underlined substrings in "computer" and "computation" only diffe