SDE

You are given a positive integer ‘N’. Your task is to print all prime numbers less than or equal to N.

Note: A prime number is a natural number that is divisible only by 1 and itself. Example - 2, 3, 17, etc.

You can assume that the value of N will always be greater than 1. So, the answer will always exist.

Given an array ARR of N integers and an integer S. The task is to find whether there exists a subarray(positive length) of the given array such that the sum of elements of the subarray equals to S or not. If any subarray is found, return the start and end index (0 based index) of the subarray. Otherwise, consider both the START and END indexes as -1.

Note:

If two or more such subarrays exist, return any subarray.

For Example: If the given array is [1,2,3,4] and the value of S is equal to 7. Then there are two possible subarrays having sums equal to S are [1,2,3] and [3,4].

You are given a string 'STR' of length 'N'. You need to return a string that will contain all the characters present at the prime indices of the original string. The relative order of characters in the new string should be exactly the same as it was in the original string.

Note:

1. Prime indices are those indices that are prime numbers i.e. all the numbers except 0 and 1 which are divisible by 1 and the number itself. For eg. If a character is at index 5 in some string, then it is at a prime index, as 5 is a prime number.

2. The given string may consist of characters ‘a’-’z’, ‘A’-’Z’, ‘0’-’9’ at any place.

3. The given string follows 0-based indexing. So, assume that the first character of the given string is at index 0.