I guess what constitutes memorization depends on what you consider "learning an algorithm". Memorizing to humans doesn't really mean learning the exact input/output pairs per se. Like a student might "learn" an algorithm for differentiation (d/dx x^n = n x^(n-1)) and then differentiate 732638 x^2 just fine despite never seeing it before, but then tell you the derivative of yx^2 with respect to y is 2yx, or something. Did they really learn how to differentiate or did they just learn a common vibe around it? When teachers see that sort of regurgitation, they call it memorization, despite the input being unique from what the student had seen in the past.