1
Student
Happy numbers
Let's call happy numbers those that, as a result of a series of transformations of the form "sum of squares of digits", will turn into one. For example:
7 => 7^2 = 49,
49 => 4^2 + 9^2 = 16 + 81 = 97,
97 => 9^2 + 7^2 = 81 + 49 = 130,
130 => 1^2 + 3^2 + 0^2 = 10,
10 => 1^2 + 0^2 = 1.
Conclusion: the initial number 7 is a happy one.
isHappyNumber.js
Implement and export as default a function that should return true if the number is happy, and false if not. The number of search iterations should be limited to 10.
Tips
- Use the auxiliary function
sumOfSquareDigits()that which should take a number as input and return the "sum of squares of digits" of this number - Use
str.lengthto get a string length
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