Python program to check if the given number is Happy Number

# Function to return the sum of squares of digits of n
def numSquareSum(n):
    squareSum = 0
    while (n != 0):
        squareSum += (n % 10) * (n % 10)
        n = n // 10
    return squareSum

# Function to return true if n is a Happy Number
def isHappyNumber(n):
    st = set()
    while (1):
        n = numSquareSum(n)
        if (n == 1):
            return True
        if n in st:
            return False
        st.add(n)

# Example usage:
print(isHappyNumber(20))  

# Utility method to return 
# sum of square of digit of n
def numSquareSum(n):
    squareSum = 0;
    while(n):
        squareSum += (n % 10) * (n % 10);
        n = int(n / 10);
    return squareSum;
 
# method return true if
# n is Happy number
def isHappynumber(n):
 
    # initialize slow 
    # and fast by n
    slow = n;
    fast = n;
    while(True):
         
        # move slow number
        # by one iteration
        slow = numSquareSum(slow);
 
        # move fast number
        # by two iteration
        fast = numSquareSum(numSquareSum(fast));
        if(slow != fast):
            continue;
        else:
            break;
 
    # if both number meet at 1, 
    # then return true
    return (slow == 1);
 
# Driver Code
n = 13;
if (isHappynumber(n)):
    print(n , "is a Happy number");
else:
    print(n , "is not a Happy number");
 

# Method - returns true if the input is
# a happy number else returns false
def isHappynumber(n):
    if n == 1 or n == 7:
        return True
          
    Sum, x = n, n
  
    # This loop executes till the sum
    # of square of digits obtained is
    # not a single digit number
    while Sum > 9:
        Sum = 0
          
        # This loop finds the sum of
        # square of digits
        while x > 0:
            d = x % 10
            Sum += d * d
            x = int(x / 10)
         
        if Sum == 1:
            return True
              
        x = Sum
     
    if Sum == 7:
        return True
          
    return False
 
n = 13
      
if isHappynumber(n):
    print(n, "is a Happy number")
else:
    print(n, "is not a Happy number")