StringToPalindrome.java

packagearray;

importjava.util.HashMap;
importjava.util.Map;

publicclassStringToPalindrome {

publicstaticStringmakePalindrome(Strings) {
HashMap<Character, Integer> map = newHashMap<Character, Integer>();
for (charch : s.toCharArray()) {
if (!map.containsKey(ch)) {
map.put(ch, 1);
 } else {
map.put(ch, map.get(ch) + 1);
 }
 }

StringBuilderans = newStringBuilder(s);
intlow = 0, high = s.length() - 1;

for (Map.Entry<Character, Integer> entries : map.entrySet()) {
if (entries.getValue() == 1) {
ans.setCharAt((ans.length() / 2), entries.getKey());
 } else {
ans.setCharAt(low, entries.getKey());
ans.setCharAt(high, entries.getKey());
low++;
high--;
 }
 }
returnans.toString();
 }

publicstaticvoidmain(String[] args) {
Stringstr = "aabbc";
System.out.println(makePalindrome(str));
System.out.println(makePalindrome("aabbccd"));
System.out.println(makePalindrome("abccbar"));
 }
}