Frontend Engineer Intern

You are given an integer, all you have to do is to find whether this number is a Fibonacci number or not.

Fn is said to be a Fibonacci sequence such that each number in Fn is the sum of its two preceding numbers, starting with 0 and 1.

Fn = F(n-1) + F(n-2)

fn is said to be a Fibonacci number if it is a part of the Fn/Fibonacci sequence.

You are given a string ‘S’ representing a date in the “Day Month Year” format, where:

1. Day is represented as {"1st", "2nd", "3rd", "4th",”5th”, ...,”29th”, "30th", "31st"}.

2. Month is represented as {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"}.

3. Year is represented as {2020,2021 etc}

Your task is to convert the given date into “YYYY-MM-DD” format, where:

1. YYYY is a 4 digit year.

2. MM is a 2 digit month.

3. DD is a 2 digit day.

Note:

1. The given dates are guaranteed to be valid.

2. If you can’t represent a month in 2 digits then append  0 in front of the month. Eg: if the month is Jan, represent it as 01 and not as 1 in the answer.

3. If you can’t represent a day in 2 digits then append 0 in front of the day. Eg: if the day is 5, represent it as 05 and not as 5 in the answer.

Implement a function in JavaScript that retries a promise N times with a delay between each attempt.

Create a retryWithDelay function that repeatedly calls an API until the promise resolves or the maximum retry limit is reached. A delay should be applied between each retry.

Function Signature:
retryWithDelay(apiCall, maxRetries, delay)

Parameters:

• apiCall → A function that returns a Promise
• maxRetries → Maximum number of retry attempts (integer)
• delay → Delay in milliseconds between retries (integer)

Return Value:

• Returns a Promise
• Resolves with the result of apiCall if it succeeds
• Rejects if all retry attempts are exhausted

You have been given a sorted array/list of integers 'arr' of size 'n' and an integer 'x'.

Find the total number of occurrences of 'x' in the array/list.

Example:

Input: 'n' = 7, 'x' = 3
'arr' = [1, 1, 1, 2, 2, 3, 3]

Output: 2

Explanation: Total occurrences of '3' in the array 'arr' is 2.

You are given an array of 1000 API functions, where each function returns a Promise.

Implement a function that executes these APIs in batches of a given size. All APIs in a batch must run in parallel, and the next batch should start only after the current batch completes. The results must be returned in the same order as the input APIs.

Function Signature:
async function callApisInBatches(apis, batchSize)

Parameters:

• apis → An array of functions that return Promises
• batchSize → Number of APIs to execute in each batch

Return Value:

• Returns a Promise
• Resolves to an array containing the results of all API calls in the same order as the input