navigationController 跳越Pop

//    [self.navigationController popToViewController:[self.navigationController.viewControllers objectAtIndex:0] animated:YES];
    
//    NSArray *controllers = self.navigationController.viewControllers;
//    NSInteger count = [controllers count] - 3;
//    UIViewController *ctrl = (UIViewController *)[controllers objectAtIndex:count];
//    [self.navigationController popToViewController:ctrl animated:YES];