From 3f999eb382c3627154cb0dacd8abda695aba1519 Mon Sep 17 00:00:00 2001
From: tingleshao <tingleshao@gmail.com>
Date: Mon, 11 Mar 2013 11:53:57 -0400
Subject: [PATCH] problem 55

---
 problem51to60/problem53.py |  2 ++
 problem51to60/problem55.py | 21 +++++++++++++++++++++
 2 files changed, 23 insertions(+)
 create mode 100644 problem51to60/problem55.py

diff --git a/problem51to60/problem53.py b/problem51to60/problem53.py
index bd15af1..add6af1 100644
--- a/problem51to60/problem53.py
+++ b/problem51to60/problem53.py
@@ -1,4 +1,6 @@
 # problem 53 
+# straight forward solution is very fast
+#  time complexity: O(n^2 * n) = O(n^3)   
 def combin(n,r):
 	return frac(n) / ( frac(n-r) * frac(r))
 	
diff --git a/problem51to60/problem55.py b/problem51to60/problem55.py
new file mode 100644
index 0000000..61d832d
--- /dev/null
+++ b/problem51to60/problem55.py
@@ -0,0 +1,21 @@
+# problem 55
+def is_palindrome(n):
+	orig_n = n
+	n_str = str(n)
+	n_rev = int(n_str[::-1])
+	for i in range(50):
+		sum = n_rev + n
+		if str(sum) == str(sum)[::-1]:
+			print str(orig_n)+ " is palindromic!"
+			return True
+		n = sum
+		n_rev = int(str(n)[::-1])
+	return False
+	
+count = 0
+for i in range(1,10000):
+	if not is_palindrome(i):
+		count += 1
+		
+print count
+