Perfect squares sum
Given a positive integer n (1 <= n <= 1e6), return the least number of perfect squares (1, 4, 9, 16, ...) that sum to n. For example 12 = 4 + 4 + 4 needs 3, and 13 = 4 + 9 needs 2. An O(sqrt(n)) number-theoretic solution exists; the O(n*sqrt(n)) DP also works but is slower.
Implement
num_squares(n: int) → intExamples
in
[12]out3What a strong answer looks like
State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.
0:00 of about 30 min
solution.py
InputExpectedGot
[12]3not run yetsample