public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  l : for ( int t = sc . nextInt ( ) ;
  t -- > 0 ;
  ) {
    int n = sc . nextInt ( ) , k = sc . nextInt ( ) ;
    String s = sc . next ( ) ;
    if ( s . substring ( 0 , k ) . equals ( reverse ( s . substring ( n - k , n ) ) ) && k * 2 < n ) System . out . println ( "YES" ) ;
    else System . out . println ( "NO" ) ;
  }
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; l : for ( int t = sc . nextInt ( ) ; t -- > 0 ; ) { int n = sc . nextInt ( ) , k = sc . nextInt ( ) ; String s = sc . next ( ) ; if ( s . substring ( 0 , k ) . equals ( reverse ( s . substring ( n - k , n ) ) ) && k * 2 < n ) System . out . println ( " YES " ) ; else System . out . println ( " NO " ) ; } }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (array_type element: (type_identifier) dimensions: (dimensions)) name: (identifier))) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list (field_access object: (identifier) field: (identifier)))))) (labeled_statement (identifier) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) condition: (binary_expression left: (update_expression (identifier)) right: (decimal_integer_literal)) body: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (decimal_integer_literal) (identifier))) name: (identifier) arguments: (argument_list (method_invocation name: (identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (identifier)) (identifier))))))) right: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (identifier)))) consequence: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))) alternative: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal))))))))))