# GOCC15: Google’s Online Challenge for Internship (India)

• Difficulty Level : Expert
• Last Updated : 22 Jul, 2021

I came to know about the opportunity through https://careers.google.com/jobs/results/ Google’s website. Applied for the same with my resume. After two weeks got a mail Invite participating in the coding round. The mail had a unique ID and got the passkey(for login) on the day of the coding round1 (29th Aug 2020). The slot was open from 15:00 to 17:00 IST.

A coding round was conducted on the HackerEarth platform. The test duration was 60 minutes consisting of two coding questions, every 30 points. I partially solved 2nd one, the solution didn’t suffice for test cases with large inputs.

A Special String: You are given a string S consisting of lowercase Latin alphabets a-z. Find the minimum number of characters that must be changed to make S special. A string S is said to be special if and only if for all (S[i], S[j] ) where (1 ≤ I ≤ N/2) and (N/2 + 1 ≤ j ≤ N) one of the following conditions is true

• S[i] > S[j]
• S[i] < S[j]
• S[i] = S[j]

S[i] represents the ith character of string S (1 based Indexing ).

Input Format:

• The first line contains an integer T denoting the number of test cases.
• The first line of each test case contains an integer N denoting the length of S.
• The second line of each test case contains a string S.

Output format: Print an integer denoting the minimum number of changes required for each test case in a new line.

Constraints

1 ≤ T ≤ 5

1 ≤ N ≤ 10

N is even

Example :

```Input:  1
6
aababc
Output: 2```

Explanation: Change S[4] = ‘d’ (1 based indexing) Change S[5] = ‘d’ New string = ‘aabddc’ Now all pair (S[i],S[j]) satisfy the second condition, S[i] < S[j]

Generating Sequence: You are given two strings A of length N and B of length M. These strings contain lowercase English alphabets. You are also given an integer K. You can change the character of x in string A to any other character y. The cost of this conversion is abs( ASCII(x)- ASCII(y) ). Find the minimum cost required such that the length of the longest common subsequence (LCS) of A and B is at least K.

Note:

• A subsequence of A string can be obtained by deleting zero or more characters in A.
• The longest common subsequence of two strings of A and B is a subsequence of A and B and has the maximum length among all strings that are a subsequence of A and B that would be multiple subsequences for two provided strings for example an LCS of vera and eats is ea.

Input Format:

• The first line contains an integer T denoting the number of test cases for each test case.
• The first line of each test case contains three space-separated integers N, M, and K.
• The next line of each test case contains a string A.
• The next line of each test case contains a string B.

Output format: For each test case, print the minimum cost required in a new line.

Constraints

1 ≤ T ≤ 10

1 ≤ N, M ≤ 200

0 ≤ K ≤ min( N, M )

Example:

```Input:  2
5 4 3
abcba
acyx
3 3 3
abc
abc
Output: 22
0```

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