static int countSubstringWithEqualEnds ( String s ) {
  int result = 0 ;
  int n = s . length ( ) ;
  int [ ] count = new int [ MAX_CHAR ] ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) count [ s . charAt ( i ) - 'a' ] ++ ;
  for ( int i = 0 ;
  i < MAX_CHAR ;
  i ++ ) result += ( count [ i ] * ( count [ i ] + 1 ) / 2 ) ;
  return result ;
}

static int countSubstringWithEqualEnds ( String s ) { int result = 0 ; int n = s . length ( ) ; int [ ] count = new int [ MAX_CHAR ] ; for ( int i = 0 ; i < n ; i ++ ) count [ s . charAt ( i ) - ' a ' ] ++ ; for ( int i = 0 ; i < MAX_CHAR ; i ++ ) result += ( count [ i ] * ( count [ i ] + 1 ) / 2 ) ; return result ; }
(method_declaration (modifiers) type: (integral_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (type_identifier) name: (identifier))) body: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (array_type element: (integral_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (identifier))))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (expression_statement (update_expression (array_access array: (identifier) index: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (character_literal)))))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (expression_statement (assignment_expression left: (identifier) right: (parenthesized_expression (binary_expression left: (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (parenthesized_expression (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (decimal_integer_literal)))) right: (decimal_integer_literal)))))) (return_statement (identifier))))