// 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>