Pretty approachable once you realize you just need to find the positions where the two strings differ and check if swapping fixes it.
First, clarify the problem: you can swap any two characters within one string at most once, and the goal is to make the strings identical. Then, compare the strings to find mismatched positions; if there are zero mismatches, return true; if there are exactly two mismatches, check if swapping the characters at those positions in one string resolves the mismatches; otherwise, return false.
Pro tip: Mention that the solution is O(n) time and O(1) space, and discuss edge cases like strings of length 1 or when multiple swaps could fix the mismatches but only one is allowed.
Confirm that the swap must be within one string and that at most one swap is allowed. Also, confirm that the strings are of equal length and consist of lowercase letters (or any specific character set).
Iterate through both strings simultaneously and record the indices where characters differ. If the number of mismatches is not 0 or 2, return false immediately.
If there are no mismatches, the strings are already identical, so return true.
If there are exactly two mismatches at indices i and j, check if swapping s1[i] with s1[j] makes s1 equal to s2. This is equivalent to checking if s1[i] == s2[j] and s1[j] == s2[i].
If the swap condition holds, return true; otherwise, return false.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
First, clarify that the strings must have the same length and character frequencies to be anagrams. Then, model the problem as finding the minimum number of swaps to transform one string into the other, and compare that to k. Use a graph-based approach where each mismatched position forms an edge between characters, and the minimum swaps equals the sum of (cycle length - 1) for each cycle in the mismatch graph.
Pro tip: Mention that the minimum swaps can be computed in O(n) time using a visited array to detect cycles, and emphasize that this is optimal because each swap can fix at most one cycle. Also, note that if the strings are already anagrams, the answer is 0 swaps, which is a quick edge case to check.
Verify that both strings have the same length and identical character frequency counts. If not, they can never be anagrams, so return false immediately.
Compare the strings character by character and record positions where they differ. These mismatches define the transformation needed.
Treat each mismatched position as a directed edge from the character in string1 to the character in string2. This graph will consist of disjoint cycles because the frequency counts are equal.
For each cycle of length L, the minimum number of swaps needed to resolve it is L - 1. Sum these values across all cycles to get the total minimum swaps.
If the total minimum swaps is less than or equal to k, return true; otherwise, return false. Also consider that if k is larger than needed, extra swaps can be wasted by swapping identical characters.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.