reverse char array concode_field_sep PlaceHolder placeHolder concode_field_sep boolean isUniqueChars concode_elem_sep boolean isPermutation concode_elem_sep int searchString concode_elem_sep char findFirstUniqueChar concode_elem_sep String compress concode_elem_sep boolean isPermutationOfPalindrome concode_elem_sep String reverseByWord concode_elem_sep int longestSubstring concode_elem_sep String sort concode_elem_sep String urlify concode_elem_sep String lookAndSay