Problem - Perfect Squares

Given an integer $n$, return the least number of perfect square numbers that sum to $n$. For example, $12 = 4 + 4 + 4$, so the answer is $3$.

This problem uses sequences in a different way: the sequence of perfect squares $1, 4, 9, 16, 25, ...$ forms the building blocks.

You need dynamic programming here, but understanding that you're working with the sequence $k^2$ for $k = 1, 2, 3, ...$ helps you structure the solution.