# Parseltongue by Helen Yu tags: strings, validation, regex ## Summary > Hermione has come up with a precise formula for determining whether or not a phrase was ssspoken by a parssseltongue (a reference from the Harry Potter universe; the language of ssserpents and those who can converse with them). > Each word in a sssentence must contain either: > At least 2 instances of the letter "s" (i.e. must be together ss), or... > Zero instanc ## Instructions Hermione has come up with a precise formula for determining whether or not a phrase was ssspoken by a parssseltongue (_a reference from the Harry Potter universe; the language of ssserpents and those who can converse with them_). Each word in a sssentence must contain either: 1. At least 2 instances of the letter "s" (i.e. must be together `ss`), or... 2. Zero instances of the letter "s". ### Examples ``` isParselTongue("Sshe ssselectss to eat that apple. ") ➞ true isParselTongue("She ssselects to eat that apple. ") ➞ false // "She" only contains one "s". isParselTongue("Beatrice samples lemonade") ➞ false // While "samples" has 2 instances of "s", they are not together. isParselTongue("You ssseldom sssspeak sso boldly, ssso messmerizingly.") ➞ true ``` ### Notes There should be no words with only one instance of the letter "s" (see example #2).