Python3 Program to Find Maximum value possible by rotating digits of a given number

Last Updated : 06 Sep, 2024

Given a positive integer N, the task is to find the maximum value among all the rotations of the digits of the integer N.

Examples:

Input: N = 657
Output: 765
Explanation: All rotations of 657 are {657, 576, 765}. The maximum value among all these rotations is 765.
Input: N = 7092
Output: 9270
Explanation:
All rotations of 7092 are {7092, 2709, 9270, 0927}. The maximum value among all these rotations is 9270.

Approach: The idea is to find all rotations of the number N and print the maximum among all the numbers generated. Follow the steps below to solve the problem:

Count the number of digits present in the number N, i.e. upper bound of log₁₀N.
Initialize a variable, say ans with the value of N, to store the resultant maximum number generated.
Iterate over the range [1, log₁₀(N) - 1] and perform the following steps:
- Update the value of N with its next rotation.
- Now, if the next rotation generated exceeds ans, then update ans with the rotated value of N
After completing the above steps, print the value of ans as the required answer.

Below is the implementation of the above approach:

# Python program for the above approach

# Function to find the maximum value
# possible by rotations of digits of N
def findLargestRotation(num):
  
    # Store the required result
    ans = num
    
    # Store the number of digits
    length = len(str(num))
    x = 10**(length - 1)
    
    # Iterate over the range[1, len-1]
    for i in range(1, length):
      
        # Store the unit's digit
        lastDigit = num % 10
        
        # Store the remaining number
        num = num // 10
        
        # Find the next rotation
        num += (lastDigit * x)
        
        # If the current rotation is
        # greater than the overall
        # answer, then update answer
        if (num > ans):
            ans = num
            
    # Print the result
    print(ans)

# Driver Code
N = 657
findLargestRotation(N)

# This code is contributed by rohitsingh07052.

 
# Python program for the above approach
​# Function to find the maximum value# possible by rotations of digits of Ndef findLargestRotation(num):      # Store the required result    ans = num        # Store the number of digits    length = len(str(num))    x = 10**(length - 1)        # Iterate over the range[1, len-1]    for i in range(1, length):              # Store the unit's digit        lastDigit = num % 10                # Store the remaining number        num = num // 10                # Find the next rotation        num += (lastDigit * x)                # If the current rotation is        # greater than the overall        # answer, then update answer        if (num > ans):            ans = num                # Print the result    print(ans)​# Driver CodeN = 657findLargestRotation(N)​# This code is contributed by rohitsingh07052.