title: how to calculate XOR (dyadic) convolution with time complexity O(n log n)
body: <p><img src="https://i.stack.imgur.com/TXF2q.png" alt="enter image description here" /></p>
  <p>“⊕” is the bitwise XOR operation.</p>
  <p>I think Karatsuba’s algorithm may be used to solve the problem, but when I try to use XOR instead of &quot;+&quot; in the Karatsuba’s algorithm, it is tough to get the sub-problem.</p>