PalindromePermutation.java

package com.example.interview;

import java.util.HashMap;
import java.util.Map;

public class PalindromePermutation {


    public static boolean isPalindromePermutation(String value) {
        Map<Character, Integer> counts = countCharacters(value);

        boolean odd = false;

        for(int count : counts.values()) {
            if (count % 2 == 1) {
                if (odd) {
                    return false;
                } else {
                    odd = true;
                }
            }
        }

        return true;
    }

    private static Map<Character, Integer> countCharacters(String value) {
        Map<Character, Integer> counts = new HashMap<>();

        for (int i = 0; i < value.length(); i++){
            Character c = Character.toLowerCase(value.charAt(i));
            if (c >= 'a' && c <= 'z') {
                int count = counts.getOrDefault(c, 0);
                counts.put(c, count + 1);
            }
        }
        return counts;
    }
}