Naming a Company
You are given an array of strings ideas that represents a list of names to be used in the process of naming a company. The process of naming a company is as follows:
- Choose 2 distinct names from
ideas, call themideaAandideaB. - Swap the first letters of
ideaAandideaBwith each other. - If both of the new names are not found in the original
ideas, then the nameideaA ideaB(the concatenation ofideaAandideaB, separated by a space) is a valid company name. - Otherwise, it is not a valid name.
Return the number of distinct valid names for the company.
Example 1
Input
ideas = ["coffee","donuts","time","toffee"]Output
6There are 6 valid ordered selections, including ("coffee", "donuts") producing "doffee conuts" and ("donuts", "coffee") producing "conuts doffee".
Example 2
Input
ideas = ["lack","back"]Output
0There are no valid selections, so 0 is returned.
Constraints
- 2 <= ideas.length <= 5 * 10^4
- 1 <= ideas[i].length <= 10
- ideas[i] consists of lowercase English letters.
- All the strings in ideas are unique.