static int findMinSwaps ( String s , int k ) {
  int ans = 0 ;
  int c_one = 0 , c_zero = 0 ;
  for ( int i = s . length ( ) - 1 ;
  i >= 0 ;
  i -- ) {
    if ( s . charAt ( i ) == '1' ) c_one ++ ;
    if ( s . charAt ( i ) == '0' ) {
      c_zero ++ ;
      ans += c_one ;
    }
    if ( c_zero == k ) break ;
  }
  if ( c_zero < k ) return - 1 ;
  return ans ;
}

static int findMinSwaps ( String s , int k ) { int ans = 0 ; int c_one = 0 , c_zero = 0 ; for ( int i = s . length ( ) - 1 ; i >= 0 ; i -- ) { if ( s . charAt ( i ) == '1' ) c_one ++ ; if ( s . charAt ( i ) == '0' ) { c_zero ++ ; ans += c_one ; } if ( c_zero == k ) break ; } if ( c_zero < k ) return - 1 ; return ans ; }
(method_declaration (modifiers) type: (integral_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (type_identifier) 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) value: (decimal_integer_literal)) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (decimal_integer_literal)))) condition: (binary_expression left: (identifier) right: (decimal_integer_literal)) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (character_literal))) consequence: (expression_statement (update_expression (identifier)))) (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (character_literal))) consequence: (block (expression_statement (update_expression (identifier))) (expression_statement (assignment_expression left: (identifier) right: (identifier))))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (break_statement)))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (return_statement (unary_expression operand: (decimal_integer_literal)))) (return_statement (identifier))))