SDE - 1

In a database, each stored file is named by a string of size ‘N’. But due to some error in the security, some of the files got infected by a virus. Given two strings ‘A’ and ‘B’ and a virus string ‘C’, Your task is to tell the number of files that are not affected by the virus. An unaffected file follows the given conditions:

The name of the file should be greater than or equal to the string ‘A’.
The name of the file should be less than or equal to string ‘B’.
The name of the file should not contain the virus string as a substring ‘C’.
Since the answer can be very large, print answer % (10^9 + 7).

For Example

If N=2 and string ‘A’ = “bc” and string ‘B’ = “bm” and virus string ‘C’ = ”g”.So the files that are not affected are “bc”, “bd”, “be”, “bf”, “bh”, “bi”, “bj”, “bk”, “bl”.

You are given a string 'STR' of length 'N' consisting of lowercase English Alphabet letters. Your task is to return the count of minimum characters to be added to make the string a palindrome.

You can add any number of characters at any positions in the string like in the beginning, or between two characters of the string or at the end of the string.

For example:

For the given string “deed”, the string is already a palindrome, thus, minimum characters needed to be added are 0. 

Similarly, for the given string “abb”, the minimum characters needed is 1 i.e. ‘a’ which is to be added to the end of the string,  which makes the string “abba”, which is a palindrome.   

You are the HR of the Ninja team and planning to hire ‘M’ candidates out of ‘N’ candidates to form a paid group. The candidates have been evaluated on the basis of their skills and have been asked for their minimum salary expectations. So, you are given two arrays, ‘SKILL’ and ‘EXPECTED_SALARY’, where ‘SKILL[i]’ and ‘EXPECTED_SALARY[i]’ represent the skill and minimum salary expectation of ‘i-th’ candidate, respectively. You have to consider the following two rules for hiring a group of ‘M’ candidates:

1) Every candidate in the paid group should be paid in the ratio of their skill compared to other candidates in the paid group.
2) The minimum salary expectation of every candidate in the paid group should be fulfilled.

You have to return the minimum amount of money required to hire ‘M’ candidates as per the above-mentioned rules.

Note:

Answers which are within the range 10^-6 of the correct answer will be considered correct.

You have been given a Binary Tree of distinct integers and two nodes ‘X’ and ‘Y’. You are supposed to return the LCA (Lowest Common Ancestor) of ‘X’ and ‘Y’.

The LCA of ‘X’ and ‘Y’ in the binary tree is the shared ancestor of ‘X’ and ‘Y’ that is located farthest from the root.

Note :

You may assume that given ‘X’ and ‘Y’ definitely exist in the given binary tree.

For example :

For the given binary tree

LCA of ‘X’ and ‘Y’ is highlighted in yellow colour.

You have given a URL id – 'N' consisting of only digits. Your task is to generate a short URL for the given URL id.

To generate a short URL, you need to convert the given URL id to 62 base number where digits of the number are:[“0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ”] i.e “0” corresponds to 0, “a” corresponds to 10, “Z” corresponds to 61, and “10” corresponds to 62, “11” corresponds to 63, and so on….

Follow Up:

Can you solve this in logarithmic time and space complexity?