static int minReplacement ( String s , int len ) {
  int ans = 0 ;
  for ( int i = 0 ;
  i < len ;
  i ++ ) {
    if ( i % 2 == 0 && s . charAt ( i ) == '1' ) ans ++ ;
    if ( i % 2 == 1 && s . charAt ( i ) == '0' ) ans ++ ;
  }
  return Math . min ( ans , len - ans ) ;
}

static int minReplacement ( String s , int len ) { int ans = 0 ; for ( int i = 0 ; i < len ; i ++ ) { if ( i % 2 == 0 && s . charAt ( i ) == '1' ) ans ++ ; if ( i % 2 == 1 && s . charAt ( i ) == '0' ) ans ++ ; } return Math . min ( ans , len - 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))) (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 (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal)) right: (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: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal)) right: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (character_literal)))) consequence: (expression_statement (update_expression (identifier)))))) (return_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (binary_expression left: (identifier) right: (identifier)))))))