tasks a-s

Task/Polynomial-long-division/Python/polynomial-long-division.py

@@ -0,0 +1,34 @@
+# -*- coding: utf-8 -*-
+
+from itertools import izip
+from math import fabs
+
+def degree(poly):
+    while poly and poly[-1] == 0:
+        poly.pop()   # normalize
+    return len(poly)-1
+
+def poly_div(N, D):
+    dD = degree(D)
+    dN = degree(N)
+    if dD < 0: raise ZeroDivisionError
+    if dN >= dD:
+        q = [0] * dN
+        while dN >= dD:
+            d = [0]*(dN - dD) + D
+            mult = q[dN - dD] = N[-1] / float(d[-1])
+            d = [coeff*mult for coeff in d]
+            N = [fabs ( coeffN - coeffd ) for coeffN, coeffd in izip(N, d)]
+            dN = degree(N)
+        r = N
+    else:
+        q = [0]
+        r = N
+    return q, r
+
+if __name__ == '__main__':
+    print "POLYNOMIAL LONG DIVISION"
+    N = [-42, 0, -12, 1]
+    D = [-3, 1, 0, 0]
+    print "  %s / %s =" % (N,D),
+    print " %s remainder %s" % poly_div(N, D)