277. Strings That Have Two Letters Swapped

Strings That Have Two Letters Swapped

You are given a string name and a list of strings nameList. Return every string from nameList that can be made equal to name by swapping exactly two characters in that string.

Matching Rules

A candidate string must have the same length as name.
Exactly two positions in the candidate string must differ from name.
Swapping the characters at those two positions must make the candidate equal to name.
A candidate that is already equal to name is not a match because no two different characters need to be swapped.
Character comparisons are case-sensitive.
Return matching strings in the same order in which they appear in nameList.
If the same matching string appears multiple times, include every occurrence.

Method

Find Names With Two Letters Swapped

List<String> findNamesWithTwoLettersSwapped(String name, List<String> nameList)

name is the target string.
nameList contains the candidate strings.
Return all candidates that satisfy the matching rules.

Constraints

1 ≤ name.length() ≤ 100,000
1 ≤ nameList.size() ≤ 100,000
1 ≤ nameList.get(i).length() ≤ 100,000
The total number of characters across all strings in nameList does not exceed 1,000,000.
name and every string in nameList contain English letters.

Examples

Example 1

findNamesWithTwoLettersSwapped(name = "market", nameList = List.of("makret", "market", "masket", "markte", "planet"))

Output: ["makret", "markte"]

In "makret", swapping 'k' and 'r' produces "market". In "markte", swapping the final two characters also produces "market".

Example 2

findNamesWithTwoLettersSwapped(name = "stone", nameList = List.of("stnoe", "sotne", "tones", "stone", "stnoe"))

Output: ["stnoe", "sotne", "stnoe"]

The matching strings differ from "stone" at exactly two positions, and swapping those characters produces the target. The duplicate occurrence is preserved.

Example 3

findNamesWithTwoLettersSwapped(name = "code", nameList = List.of("cope", "codes", "CODE", "deco"))

Output: []

None of the candidates can be transformed into "code" using exactly one swap of two characters.