SDE - 1

You have 'N' cakes of different names. You want to choose exactly 3 cakes out of these 'N' cakes. The name of the ith cake is 'S[i]' (0 <= i < 'N'). The three chosen cakes should follow the following conditions.

The name of the cake should start with 'c', 'a', 'k', 'e', or 's'.
No two cakes should begin with the same letter.

Return the number of ways to choose three cakes irrespective of the order.

Note : Assume 0-based indexing.

For example:

Let 'N' = 4, S = ["choco", "apple", "kesar", "strawberry"].
There exist 4 different ways to choose three cakes following all the required conditions i.e. {"choco", "apple", "kesar"}, {"choco", "apple", "strawberry"}, {"choco", "strawberry", "kesar"}, {"strawberry", "apple", "kesar"}.

Mr. X. is a professional robber planning to rob houses along a street. Each house has a certain amount of money hidden.

Meanwhile, adjacent houses have a security system connected, and it will automatically contact the police if two neighboring houses were broken into the same night.

You are given an array/list of non-negative integers 'A' representing the amount of money hidden at each house. Your task is to return the maximum amount of money Mr. X can rob tonight without alerting the police.

Example:

Input: [1,2,3,1]

Output: 4

Mr. X. can rob the first house and the third house, total money = 1 + 3.
Hence, the total money robbed by Mr. X. is 4.