static int calculate ( int a [ ] , int n ) {
  int maximum = Arrays . stream ( a ) . max ( ) . getAsInt ( ) ;
  int frequency [ ] = new int [ maximum + 1 ] ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    frequency [ a [ i ] ] += 1 ;
  }
  int answer = 0 ;
  for ( int i = 0 ;
  i < ( maximum ) + 1 ;
  i ++ ) {
    answer = answer + frequency [ i ] * ( frequency [ i ] - 1 ) ;
  }
  return answer / 2 ;
}

static int calculate ( int a [ ] , int n ) { int maximum = Arrays . stream ( a ) . max ( ) . getAsInt ( ) ; int frequency [ ] = new int [ maximum + 1 ] ; for ( int i = 0 ; i < n ; i ++ ) { frequency [ a [ i ] ] += 1 ; } int answer = 0 ; for ( int i = 0 ; i < ( maximum ) + 1 ; i ++ ) { answer = answer + frequency [ i ] * ( frequency [ i ] - 1 ) ; } return answer / 2 ; }
(method_declaration (modifiers) type: (integral_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier) dimensions: (dimensions)) (formal_parameter type: (integral_type) name: (identifier))) body: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (method_invocation object: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) name: (identifier) arguments: (argument_list)) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) dimensions: (dimensions) value: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (binary_expression left: (identifier) right: (decimal_integer_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: (block (expression_statement (assignment_expression left: (array_access array: (identifier) index: (array_access array: (identifier) index: (identifier))) right: (decimal_integer_literal))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_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: (binary_expression left: (parenthesized_expression (identifier)) right: (decimal_integer_literal))) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (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))))))))) (return_statement (binary_expression left: (identifier) right: (decimal_integer_literal)))))