Python3 Program to Check if a string can be obtained by rotating another string 2 places

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Given two strings, the task is to find if a string can be obtained by rotating another string two places.

Examples:

Input: string1 = “amazon”, string2 = “azonam”
Output: Yes
// rotated anti-clockwise
Input: string1 = “amazon”, string2 = “onamaz”
Output: Yes
// rotated clockwise

Asked in: Amazon Interview

1- There can be only two cases:
    a) Clockwise rotated
    b) Anti-clockwise rotated

2- If clockwise rotated that means elements
   are shifted in right.
   So, check if a substring[2.... len-1] of 
   string2 when concatenated with substring[0,1]
   of string2 is equal to string1. Then, return true.

3- Else, check if it is rotated anti-clockwise 
   that means elements are shifted to left.
   So, check if concatenation of substring[len-2, len-1]
   with substring[0....len-3] makes it equals to
   string1. Then return true.

4- Else, return false.

Below is the implementation of the above approach.

Python3

# Python 3 program to check if a string 
# is two time rotation of another string.
 
# Function to check if string2 is 
# obtained by string 1
def isRotated(str1, str2):
    if (len(str1) != len(str2)):
        return False
     
    if(len(str1) < 2):
        return str1 == str2
    clock_rot = ""
    anticlock_rot = ""
    l = len(str2)
 
    # Initialize string as anti-clockwise 
    # rotation
    anticlock_rot = (anticlock_rot +
                     str2[l - 2:] +
                     str2[0: l - 2])
     
    # Initialize string as clock wise 
    # rotation
    clock_rot = clock_rot + str2[2:] + str2[0:2]
 
    # check if any of them is equal to string1
    return (str1 == clock_rot or
            str1 == anticlock_rot)
 
# Driver code
if __name__ == "__main__":
     
    str1 = "zambiatek"
    str2 = "eksge"
if isRotated(str1, str2):
    print("Yes")  
else:
    print("No")
# This code is contributed by ita_c

Output:

Yes

Time Complexity: O(n), where n is the size of the given strings.

Please refer complete article on Check if a string can be obtained by rotating another string 2 places for more details!

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