LongestPalindrome.java

package string;
/**
 * Created by gouthamvidyapradhan on 20/03/2019
 * Given a string which consists of lowercase or uppercase letters, find the length of the longest palindromes that
 * can be built with those letters.
 *
 * This is case sensitive, for example "Aa" is not considered a palindrome here.
 *
 * Note:
 * Assume the length of given string will not exceed 1,010.
 *
 * Example:
 *
 * Input:
 * "abccccdd"
 *
 * Output:
 * 7
 *
 * Explanation:
 * One longest palindrome that can be built is "dccaccd", whose length is 7.
 */
import java.util.*;

public class LongestPalindrome {

    /**
     * Main method
     * @param args
     */
    public static void main(String[] args) {
        int result = new LongestPalindrome().longestPalindrome(
                "asdfasdf");
        System.out.println(result);
    }

    public int longestPalindrome(String s) {
        Map<Character, Integer> map = new HashMap<>();
        for(char c : s.toCharArray()){
            map.putIfAbsent(c, 0);
            int count = map.get(c);
            map.put(c, count + 1);
        }
        int max = 0;
        boolean odd = false;
        for(char c : map.keySet()){
            int count = map.get(c);
            max += count;
            if((count % 2) != 0){
                max --;
                odd = true;
            }
        }
        if(odd) max ++;
        return max;
    }
}