SDE - 1

You are given an array/list 'ARR' of ‘N’ integers and an integer value ‘TARGET’. You need to check whether there exist four numbers (ARR[i], ARR[j], ARR[k], ARR[l]) such that (0 <= i < j < k < l < N) and ARR[i] + ARR[j] + ARR[k] + ARR[l] = 'TARGET'.

Note:

1. All four numbers should exist at different indices in the given array.
2. The answer is case-sensitive.

Ninja has been given a program to do basic string compression. For a character that is consecutively repeated more than once, he needs to replace the consecutive duplicate occurrences with the count of repetitions.

Example:

If a string has 'x' repeated 5 times, replace this "xxxxx" with "x5".

The string is compressed only when the repeated character count is more than 1.

Note :

The consecutive count of every character in the input string is less than or equal to 9.

You have been given an integer array/list (ARR) of size N. You have to return an array/list PRODUCT such that PRODUCT[i] is equal to the product of all the elements of ARR except ARR[i]

 Note :

Each product can cross the integer limits, so we should take modulo of the operation. 

Take MOD = 10^9 + 7 to always stay in the limits.

Follow up :

Can you try solving the problem in O(1) space?

You have been given a string STR. Your task is to find the total number of palindromic substrings of STR.

Example :

If the input string is "abbc", then all the possible palindromic substrings would be: ["a", "b", "b", c", "bb"] and hence, the output will be 5 since we have 5 substrings in total which form a palindrome.

Note :

A string is said to be a 'Palindrome' if it is read the same forwards and backwards. 
For example, “abba” is a palindrome, but “abbc” is not.

A 'Substring' is a contiguous sequence of characters within a string. 
For example, "a", "b", "c", "ab", "bc", "abc" are substrings of "abc".