Naming a Company

arrayhash tablestring

Problem Statement

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 them idea _A and idea _B .

Swap the first letters of idea _A and idea _B with each other.

If both of the new names are not found in the original ideas , then the name idea _A idea _B (the concatenation of idea _A and idea _B , 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 .

Examples

Example 1

Input: ideas = ["coffee","donuts","time","toffee"]
Output: 6
The following selections are valid:
- ("coffee", "donuts"): The company name created is "doffee conuts".
- ("donuts", "coffee"): The company name created is "conuts doffee".
- ("donuts", "time"): The company name created is "tonuts dime".
- ("donuts", "toffee"): The company name created is "tonuts doffee".
- ("time", "donuts"): The company name created is "dime tonuts".
- ("toffee", "donuts"): The company name created is "doffee tonuts".
Therefore, there are a total of 6 distinct company names.

The following are some examples of invalid selections:
- ("coffee", "time"): The name "toffee" formed after swapping already exists in the original array.
- ("time", "toffee"): Both names are still the same after swapping and exist in the original array.
- ("coffee", "toffee"): Both names formed after swapping already exist in the original array.

Example 2

Input: ideas = ["lack","back"]
Output: 0
There are no valid selections. Therefore, 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 .

😤

Hard

Difficulty

Topic Info

ModuleDSA

CategoryArray

Sub-topicHash Table