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Naming a Company
HardArraysGiven distinct lowercase words, form a company name by picking two different words, swapping their first letters, and concatenating them with a space but only if both swapped words are not already in the original set. Count the number of valid ordered pairs.
Input format (stdin): the first line has n. Each of the next n lines is a word. Output the count of valid names.
Examples
Input: 4
coffee
donuts
time
toffee
Output: 6
Six ordered pairs produce valid names.
Input: 3
lack
back
ack
Output: 4
Pairing the exclusive suffixes across first letters yields four valid names.
Constraints
- 1 <= n <= 10^5
- words are distinct lowercase
Sheets
NeetCode 250
naming-a-company.cpp2 sample tests
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Custom input (stdin)
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