Can form Palindrome?
Write a program to test whether the letters forming a string can be permuted to form a palindrome.
public static boolean canFormPalindrome(String s) {
Set<Character> charsWithOddFrequency = new HashSet<>();
for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
if (charsWithOddFrequency.contains(c)) {
charsWithOddFrequency.remove(c);
} else {
charsWithOddFrequency.add(c);
}
}
return charsWithOddFrequency.size() <= 1;
}