1 files changed, 37 insertions, 0 deletions
diff --git a/lib/fact.py b/lib/fact.py
new file mode 100644
index 0000000..ba961c4
--- /dev/null
+++ b/lib/fact.py
@@ -0,0 +1,37 @@
+# Factorize numbers -- slow, could use a table of all primes <= 2*16
+
+import sys
+import math
+
+error = 'fact.error' # exception
+
+def fact(n):
+ if n < 1: raise error # fact() argument should be >= 1
+ if n = 1: return [] # special case
+ res = []
+ _fact(n, 2, res)
+ return res
+
+def _fact(n, lowest, res):
+ highest = int(math.sqrt(float(n+1)))
+ for i in range(lowest, highest+1):
+ if n%i = 0:
+ res.append(i)
+ _fact(n/i, i, res)
+ break
+ else:
+ res.append(n)
+
+def main():
+ if len(sys.argv) > 1:
+ for arg in sys.argv[1:]:
+ n = eval(arg)
+ print n, fact(n)
+ else:
+ try:
+ while 1:
+ print fact(input())
+ except EOFError:
+ pass
+
+main()