BNY Mellon Backend Software Developer interview Questions

 

1. Validate JSON

---

Your job is to determine if an input string is valid JSON.
An easy resource for understanding JSON is here: http://www.json.org/

Your requirements:

• Determine if the input string is valid JSON.
• Return "true" if it is valid. Return "false" if it is not.

Example:

If you are given the following input data:
{"test": "Hello World"}

The output will be:
true

On the other hand, if you are given the following input data:
{"test": Hello World"}

The output will be:
false

2. HTML Entity Codes

---

Background

When working with item like HTML and XML, you often want to use replacements for normal characters.
In HTML, these are often called referenced "entities".

Problem

You will need to do a limited version of character replacement.
Specifically, you need to find these characters in an input string:

 - "<"     
 - ">"    
 - "&"    

and replace them with:

 - "<"     
 - ">"     
 - "&"    

Example

For example, if you are given this string:
Hello <World> Goodbye & World
The output would be:
Hello < World > Goodbye & World

Considerations

• Replace all of the characters
• Your code should be able to handle Unicode characters (i.e., non-English)

3. Wikipedia Article

---

In this challenge, use an HTTP GET method to retrieve information from Wikipedia.
Query https://en.wikipedia.org/w/api.php?action=parse&section=0&prop=text&format=json&page=[topic] to get the topic Wikipedia article.
Return the total number of times that the string [topic] appears in the article's text field.
Note that the search is case-sensitive.

The query response from the website is a JSON object described below:

• parse: A JSON object representing the article's parsed web page. It has following three fields:
  1. title: The article's title, as specified by the argument passed as topic.
  2. pageid: The article's Page ID.
  3. text: A JSON object that contains the Wikipedia article as an HMTL dump.

Function Description:

Complete the function getTopicCount in the editor below.
The function must return an integer, the number of times the search term topic appears in the returned text field.

getTopicCount has the following parameter(s):
topic: a string to query

4. Loading a web page

---

Imagine you just purchased a new computer, and you've opened up a web browser for the first time.
You go to the address bar type in: https://example.org

Describe what happens between the moment you press the Enter key when the page has finished loading in the browser.

Note: this is an open-ended question. You will need to decide the level of detail you want to include.

Ans: 
- When the user hits enter, the browser looks in the cache whether the corresponding IP address is present or not.
- If the IP is present in the browser cache then it renders the page from the cache.
- If IP is not present in the browser cache then it will try to find the IP for the corresponding URL in the DNS server.
- Once the browser gets the IP from DNS server, it will establish a connection and send the HTTP request to the server with that IP.
- The server will serve the browser by checking the URL and responding with HTTP response.
- The browser receives the HTTP response which is usually an HTML page which browser then renders the response in the window. 

5. Complexity of the Code Snippet

---

Consider the following code snippet:

	int a = 1;
	while (a<n){
		a = a * 2
	}

What is complexity of the above code snippet:

Pick one of the choices
- O(n)
- O(1)
- O(log(n))
- O(2^n)

The correct answer is O(log(n)).

6. Number of Paths in a Matrix

---

Consider a maze mapped to a matrix with an upper left corner at coordinates (row, column) = (0, 0).
Any movement must be in increasing row or column direction.
Determine the number of distinct paths through the maze.
Always start at position (0, 0), the top left, and end up at (max(row), max(column)), the bottom right.

Function Description:
Complete the function numberOfPaths in the editor below.
The function must return the number of paths through the matrix modulo (10^9+7).

numberOfPaths has the following parameter(s):
a[a[0], ...., a[n-1]]: an array of strings, each a row of the matrix where each character represents a column.

Constraints:

• 1 <= n, m <= 1000
• Each cell in matrix a contains either a 0 or a 1.

Input Format for Custom Testing:
Input from stdin will be a processed as follows and passed to the function. The first line contains an integer n, the number of rows in a matrix a. The next line contains an integer m, the number of columns in matrix a. The next n lines each contain a string a[i] where 0 <= i < n and |a[i]| = m.

Sample Case 0 
Sample Input 0
3
4
1 1 1 1
1 1 1 1
1 1 1 1

Sample Output 0 
10

Explanation 0

Sample Case 1 
Sample Input 1
2
2
1 1
0 1

Sample Output 1 
1

Explanation 1