Computation: N = 5; K = 3 s[0] s[1] s[2] r[0] = s[0]*s[0] + s[1]*s[1] + s[2]*s[2] + s[3]*s[3] + s[4]*s[4] r[1] = s[0]*s[1] + s[1]*s[2] + s[2]*s[3] + s[3]*s[4] + s[4]*s[5] r[2] = s[0]*s[2] + s[1]*s[3] + s[2]*s[4] + s[3]*s[5] + s[4]*s[6] Note: s[0]*s[2] + s[2]*s[4] => s[2]*(s[0] + s[4]) O[NK] => O[(N/2)K]