// Finds the last repeated character in a string.
// Scans the string from right to left using a Set to track seen characters.
// Returns the character, or ' ' if no character is repeated.
func findLastRepeatedCharacter(_ s: String) -> Character {
var seen = Set<Character>()
// Iterate through the string's characters in reverse order (right to left)
for char in s.reversed() {
// Set.insert returns a tuple where `inserted` is false if the
// element was already present in the set.
if !seen.insert(char).inserted {
return char
}
}
// Return a space character if no duplicates are found (matching C++ style)
return " "
}
// Test cases adapted from your C++ examples
let testCases = [
"abca",
"abcbd",
"abcde",
"abcdxypcbop",
"abcdxypcbadom"
]
for tc in testCases {
let result = findLastRepeatedCharacter(tc)
print("findLastRepeatedCharacter(\"\(tc)\") -> \(result)")
}
/*
run:
findLastRepeatedCharacter("abca") -> a
findLastRepeatedCharacter("abcbd") -> b
findLastRepeatedCharacter("abcde") ->
findLastRepeatedCharacter("abcdxypcbop") -> p
findLastRepeatedCharacter("abcdxypcbadom") -> d
*/
