// C++ program to get lexicographically smallest // palindrome string #include    using namespace std; // Utility method to check str is possible palindrome // after ignoring . bool isPossiblePalindrome(string str) {  int n = str.length();  for (int i=0; i<n/2; i++)  {  /* If both left and right character are not  dot and they are not equal also then it  is not possible to make this string a  palindrome */  if (str[i] != '.' &&  str[n-i-1] != '.' &&  str[i] != str[n-i-1])  return false;  }  return true; } // Returns lexicographically smallest palindrom // string if possible string smallestPalindrome(string str) {  if (!isPossiblePalindrome(str))  return 'Not Possible';  int n = str.length();  // loop through character of string  for (int i = 0; i < n; i++)  {  if (str[i] == '.')  {  // if one of character is dot replace dot  // with other character  if (str[n - i - 1] != '.')  str[i] = str[n - i - 1];  // if both character are dot then replace  // them with smallest character 'a'  else  str[i] = str[n - i - 1] = 'a';  }  }  // return the result  return str; } // Driver code to test above methods int main() {  string str = 'ab..e.c.a';  cout << smallestPalindrome(str) << endl;  return 0; } 

// Java program to get lexicographically  // smallest palindrome string class GFG  { // Utility method to check str is // possible palindrome after ignoring static boolean isPossiblePalindrome(char str[]) { int n = str.length; for (int i = 0; i < n / 2; i++) {  /* If both left and right character   are not dot and they are not   equal also then it is not   possible to make this string a  palindrome */  if (str[i] != '.' &&  str[n - i - 1] != '.' &&  str[i] != str[n - i - 1])  return false; } return true; } // Returns lexicographically smallest  // palindrome string if possible static void smallestPalindrome(char str[]) { if (!isPossiblePalindrome(str))  System.out.println('Not Possible'); int n = str.length; // loop through character of string for (int i = 0; i < n; i++) {  if (str[i] == '.')  {  // if one of character is dot   // replace dot with other character  if (str[n - i - 1] != '.')  str[i] = str[n - i - 1];  // if both character are dot   // then replace them with   // smallest character 'a'  else  str[i] = str[n - i - 1] = 'a';  } } // return the result for(int i = 0; i < n; i++)  System.out.print(str[i] + ''); } // Driver code public static void main(String[] args) {  String str = 'ab..e.c.a';  char[] s = str.toCharArray();  smallestPalindrome(s); } } // This code is contributed  // by ChitraNayal 

# Python 3 program to get lexicographically  # smallest palindrome string # Utility method to check str is  # possible palindrome after ignoring  def isPossiblePalindrome(str): n = len(str) for i in range(n // 2): # If both left and right character  # are not dot and they are not  # equal also then it is not possible  # to make this string a palindrome  if (str[i] != '.' and str[n - i - 1] != '.' and str[i] != str[n - i - 1]): return False return True # Returns lexicographically smallest # palindrome string if possible def smallestPalindrome(str): if (not isPossiblePalindrome(str)): return 'Not Possible' n = len(str) str = list(str) # loop through character of string for i in range(n): if (str[i] == '.'): # if one of character is dot  # replace dot with other character if (str[n - i - 1] != '.'): str[i] = str[n - i - 1] # if both character are dot  # then replace them with  # smallest character 'a' else: str[i] = str[n - i - 1] = 'a' # return the result return str # Driver code if __name__ == '__main__': str = 'ab..e.c.a' print(''.join(smallestPalindrome(str))) # This code is contributed by ChitraNayal 

// C# program to get lexicographically  // smallest palindrome string using System; public class GFG   {  // Utility method to check str is  // possible palindrome after ignoring  static bool isPossiblePalindrome(char []str)  {  int n = str.Length;  for (int i = 0; i < n / 2; i++)  {  /* If both left and right character   are not dot and they are not   equal also then it is not   possible to make this string a  palindrome */  if (str[i] != '.' &&  str[n - i - 1] != '.' &&  str[i] != str[n - i - 1])  return false;  }  return true;  }  // Returns lexicographically smallest   // palindrome string if possible  static void smallestPalindrome(char []str)  {  if (!isPossiblePalindrome(str))  Console.WriteLine('Not Possible');  int n = str.Length;  // loop through character of string  for (int i = 0; i < n; i++)  {  if (str[i] == '.')  {  // if one of character is dot   // replace dot with other character  if (str[n - i - 1] != '.')  str[i] = str[n - i - 1];  // if both character are dot   // then replace them with   // smallest character 'a'  else  str[i] = str[n - i - 1] = 'a';  }  }  // return the result  for(int i = 0; i < n; i++)  Console.Write(str[i] + '');  }  // Driver code  public static void Main()  {  String str = 'ab..e.c.a';  char[] s = str.ToCharArray();  smallestPalindrome(s);  } } // This code is contributed by PrinciRaj1992 

 // PHP program to get lexicographically // smallest palindrome string // Utility method to check str is // possible palindrome after ignoring function isPossiblePalindrome($str) { $n = strlen($str); for ($i = 0; $i < $n / 2; $i++) { /* If both left and right   character are not dot and   they are not equal also then   it is not possible to make this   string a palindrome */ if ($str[$i] != '.' && $str[$n - $i - 1] != '.' && $str[$i] != $str[$n - $i - 1]) return false; } return true; } // Returns lexicographically smallest  // palindrome string if possible function smallestPalindrome($str) { if (!isPossiblePalindrome($str)) return 'Not Possible'; $n = strlen($str); // loop through character of string for ($i= 0; $i < $n; $i++) { if ($str[$i] == '.') { // if one of character is dot  // replace dot with other character if ($str[$n - $i - 1] != '.') $str[$i] = $str[$n - $i - 1]; // if both character are dot  // then replace them with  // smallest character 'a' else $str[$i] = $str[$n - $i - 1] = 'a'; } } // return the result return $str; } // Driver code $str = 'ab..e.c.a'; echo smallestPalindrome($str); // This code is contributed  // by ChitraNayal ?> 

<script> // Javascript program to get lexicographically  // smallest palindrome string    // Utility method to check str is  // possible palindrome after ignoring  function isPossiblePalindrome(str)  {  let n = str.length;  for (let i = 0; i < Math.floor(n / 2); i++)  {  /* If both left and right character   are not dot and they are not   equal also then it is not   possible to make this string a  palindrome */  if (str[i] != '.' &&  str[n - i - 1] != '.' &&  str[i] != str[n - i - 1])  return false;  }    return true;  }    // Returns lexicographically smallest   // palindrome string if possible  function smallestPalindrome(str)  {  if (!isPossiblePalindrome(str))  document.write('Not Possible');    let n = str.length;    // loop through character of string  for (let i = 0; i < n; i++)  {  if (str[i] == '.')  {  // if one of character is dot   // replace dot with other character  if (str[n - i - 1] != '.')  str[i] = str[n - i - 1];    // if both character are dot   // then replace them with   // smallest character 'a'  else  str[i] = str[n - i - 1] = 'a';  }  }    // return the result  for(let i = 0; i < n; i++)  document.write(str[i] + '');    }    // Driver code  let str='ab..e.c.a';  let s = str.split('');  smallestPalindrome(s);    // This code is contributed by rag2127   </script>