CareerCup

What if we restrict equality to only the reverse strings?

E.g.

hash("baaann") != hash("banana")

Use two pointers.
Convert string to lowercase.
ignore punctuations, while incrementing/decrementing the start/end pointers.
compare pointers in each iteration, if there is a mismatch then return false.
In the end, if there is no mismatch then return true.

class Palindrome{
	public static void main(String[] args){
		isPalindrome("L*&EVe)))l");	
	}
	private static void isPalindrome(String p){
		int start = 0;
		int end = p.length()-1;
		String s = p.toLowerCase();
		char[] arr = s.toCharArray();
		while(start <= end){
			if(!Character.isLetterOrDigit(arr[start])){
				start++;
				continue;
			}
			if(!Character.isLetterOrDigit(arr[end])){
				end++;
				continue;
			}
			if(arr[start]!=arr[end]){
				System.out.println("False");
			}
			start++;
			end--;
		}
		System.out.println("True");
	}
}

You can also use a stack. Put all the characters in the stack, and then pop all those to a separate string. At the ends compare the two string. If there are equal return true, otherwise return false.

We need a frontend, which I would prefer to be made in Angular, React, or Knockoutjs.
We need access network with load balancing capabilities, for high availability.
I would personally make use of cloud computing instead of using my own premises network. I can make use of features provided by the cloud.
For storing images I would use services like S3 from AWS, or similar home-backed one.
For event e.g. LIKE, LOVE, etc I would use streaming (event processing) and messaging. I would need a distributed architecture because users can access images from anywhere, and latency is important in a timeline scroll on the app.

These sort of questions are open-ended so you can just use your wild imagination. Interviewers are normally checking your thinking abilities in terms of architecture and scalability.

If I were asked these questions, I would have responded like the following:
-Why Facebook?
World's biggest social network. Innovative people. Has a huge social impact, and it will give you an opportunity to make a difference at a global scale.
-What was the biggest technical problem that you solved?
Reaching the face-to-face interview.
-Do you have any apps on google play?
No.
-Give me a scenario where the requirements were ambiguous, what did you do?
I was asked to design URL shortening service, with two different distributed architectural patterns. I can use any two patterns I like.
I used sharding and modern multi-tier with load-balancing and scalability.