Given two strings, determine if they match exactly or can be made equal by swapping exactly one pair of characters in one of the strings. Return true if they match, false otherwise.

To solve this, first check that the two strings have the same length; if not, they can never match. Next, iterate through the strings and record the indices where the characters differ. If there are no differences, the strings are already equal, so return true. If there are exactly two differences, say at positions i and j, then swapping the characters at those positions in one string will make the strings equal if and only if s1[i]==s2[j] and s1[j]==s2[i]. If this condition holds, return true; otherwise return false. Any other number of mismatches (one or more than two) means the strings cannot be matched by a single swap, so return false. This algorithm runs in O(n) time and O(1) extra space, where n is the length of the strings.