Fast Fourier Transform, Algorithms, Pattern Matching, Convolution, Combination Sum.
result += c[i]*h h *= 10 return result if sign else -result p, q = 1234, 6789 assert fft_multiply(p, q) == p*q The step where we round of the coefficients or the C vector to the nearest integer is an important step after inverse fourier transform, due to the following reasons. In integer