Check if it is possible to create a palindrome string from given N in Python

Suppose we have a number n. We have to check whether we can create an alphabetical lowercase string from that number and check whether the string is palindrome or not. Here we will take only characters from a to j, where a = 0, b = 1... j = 9. So if the number is 42, the substring "ec" will be repeated till we reach 6 (4+2) characters "ececec", then check if this is palindrome or not.

So, if the input is like n = 43, then the output will be True. The string is "ededede" and this is palindrome.

Algorithm

To solve this, we will follow these steps ?

• temp := blank string
• s := n as string
• letters := all characters from a to j
• sum := 0
• substr := blank string
• for each digit in s, do
  • d := digit as numeric
  • substr := substr concatenate letters[d]
  • sum := sum + d
• while length of temp <= sum, do
  • temp := temp concatenate substr
• temp := temp[from index 0 to sum − 1]
• return true when temp is palindrome, otherwise false

Example

Let us see the following implementation to get better understanding ?

def isPalindrome(s):
    return s == s[::-1]

def solve(n):
    temp = ""
    s = str(n)
    letters = "abcdefghij"
    digit_sum = 0
    substr = ""
    
    for i in range(len(s)):
        d = int(s[i])
        substr += letters[d]
        digit_sum += d
    
    while len(temp) <= digit_sum:
        temp += substr
    
    temp = temp[:digit_sum]
    return isPalindrome(temp)

# Test the function
n = 43
print(solve(n))

The output of the above code is ?

True

How It Works

For n = 43:

• Digits: 4, 3
• Corresponding letters: 'e', 'd'
• Substring: "ed"
• Sum of digits: 4 + 3 = 7
• Repeat "ed" to get 7 characters: "ededede"
• Check palindrome: "ededede" == "ededede" ? True

Additional Example

Let's test with another number ?

def isPalindrome(s):
    return s == s[::-1]

def solve(n):
    temp = ""
    s = str(n)
    letters = "abcdefghij"
    digit_sum = 0
    substr = ""
    
    for i in range(len(s)):
        d = int(s[i])
        substr += letters[d]
        digit_sum += d
    
    while len(temp) <= digit_sum:
        temp += substr
    
    temp = temp[:digit_sum]
    return isPalindrome(temp)

# Test with different numbers
test_numbers = [42, 43, 11, 20]

for num in test_numbers:
    result = solve(num)
    print(f"n = {num}, Result: {result}")

The output of the above code is ?

n = 42, Result: False
n = 43, Result: True
n = 11, Result: True
n = 20, Result: False

Conclusion

This algorithm converts digits to letters, creates a repeating pattern, and checks if the resulting string of specified length is a palindrome. The key insight is mapping digits 0-9 to letters 'a'-'j' and using the sum of digits as the target string length.