public static int countSubarrays ( int a [ ] , int n , int m ) {
  int count = 0 ;
  int prefix [ ] = new int [ n ] ;
  int odd = 0 ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    prefix [ odd ] ++ ;
    if ( ( a [ i ] & 1 ) == 1 ) odd ++ ;
    if ( odd >= m ) count += prefix [ odd - m ] ;
  }
  return count ;
}

public static int countSubarrays ( int a [ ] , int n , int m ) { int count = 0 ; int prefix [ ] = new int [ n ] ; int odd = 0 ; for ( int i = 0 ; i < n ; i ++ ) { prefix [ odd ] ++ ; if ( ( a [ i ] & 1 ) == 1 ) odd ++ ; if ( odd >= m ) count += prefix [ odd - m ] ; } return count ; }
(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)) (formal_parameter type: (integral_type) 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) dimensions: (dimensions) value: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (identifier))))) (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: (identifier)) update: (update_expression (identifier)) body: (block (expression_statement (update_expression (array_access array: (identifier) index: (identifier)))) (if_statement condition: (parenthesized_expression (binary_expression left: (parenthesized_expression (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (decimal_integer_literal))) right: (decimal_integer_literal))) consequence: (expression_statement (update_expression (identifier)))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (expression_statement (assignment_expression left: (identifier) right: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (identifier)))))))) (return_statement (identifier))))