Python Program to find minimum number of rotations to obtain actual string
Given two strings s1 and s2. The task is to find out the minimum number of string rotations for the given string s1 to obtain the actual string s2. Examples:
Input : eeksg, geeks
Output: 1
Explanation: g is rotated left to obtain geeks.
Input : eksge, geeks
Output: 2
Explanation : e and g are left rotated to obtain geeks.
Approach:
- Use string slicing to rotate the string.
- Perform right rotations str1=str1[1:len(str1)]+str1[0] on string to obtain the actual string.
- Perform left rotations m=m[len(m)-1]+m[:len(m)-1] on string to obtain the actual string.
- Print the minimum of left(x) and right(y) rotations.
TIME COMPLEXITY: O(n) Below is the implementation:
python3
def findRotations(str1, str2):
x = 0
y = 0
m = str1
while True :
m = m[ len (m) - 1 ] + m[: len (m) - 1 ]
if (m = = str2):
x + = 1
break
else :
x + = 1
if x > len (str2) :
break
while True :
str1 = str1[ 1 : len (str1)] + str1[ 0 ]
if (str1 = = str2):
y + = 1
break
else :
y + = 1
if y > len (str2):
break
if x < len (str2):
print ( min (x,y))
else :
print ("given strings are not of same kind")
findRotations( 'sgeek' , 'geeks' )
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The Time and Space Complexity for all the methods are the same:
Time Complexity: O(n)
Auxiliary Space: O(n)
Last Updated :
09 Sep, 2022
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