Happy number python

Python/HappyNumber.py

@@ -0,0 +1,46 @@
+# Python program to check if a number is happy or not:
+
+# funtion to get sum of squares of the digits of a number:
+def ssd(n):
+    a = b = 0;
+    while(n > 0):
+        a = n%10
+        b += a*a
+        n //= 10
+    return b
+
+# User input:
+print("Enter Number to Check:")
+n = int(input())
+h = n;
+
+while(h != 1 and h != 4):
+    h = ssd(h)
+
+if(h == 1):
+    print(n,"is a happy number")
+elif(h == 4):
+    print(n,"is not a happy number")
+
+'''
+Explanation:
+A happy number is a number which eventually reaches 1 when replaced
+by the sum of the square of each digit. All Non happy numbers eventually
+become 4 and get stuck in an infinite cycle, therefore if a number reaches 4
+anytime in the cycle it is not a happy number
+
+Examples of Happy Numbers:
+-> 100 = 1*1 + 0*0 +0*0 = 1
+-> 13 = 1*1 + 3*3 = 10, 10 = 1*1 + 0*0 = 1
+-> 19 = 1*1 + 9*9 = 82, 82 = 8*8 + 2*2 = 68, 68 = 6*6 + 8*8 = 100, 100 = 1*1 + 0*0 + 0*0 =1
+
+Sample Input:
+Enter Number to Check:
+13
+
+Sample Output:
+13 is a happy number
+
+Time Complexity : O(log N)
+Space Complexity : O(log N)
+'''

Python/README.md

@@ -66,6 +66,8 @@ Format: -[Program name](name of the file)
 
 -[Greatest Common divisor](gcd.py)
 
+-[Happy Number](HappyNumber.py)
+
 -[Heap Sort](Heap_sort.py)
 
 -[Inorder Tree Traversal](inordder.py)
@@ -171,4 +173,3 @@ Format: -[Program name](name of the file)
 -[Unique Number From A Set of Numbers repeated twice except unique number](unique_number_repeated_twice_except_unique_number.py)
 
 -[All Hamiltonian Cycles/Paths](all_hamiltonian_cycles.py)
-