Given a string s1 and a string s2, write a snippet to say whether s2 is a rotation of s1?
(eg given s1 = ABCD and s2 = CDAB, return true, given s1 = ABCD, and s2 = ACBD , return false)
Algorithm: areRotations(str1, str2)
1. Create a temp string and store concatenation of str1 to str1 in temp. temp = str1.str1 2. If str2 is a substring of temp then str1 and str2 are rotations of each other. Example: str1 = "ABACD" str2 = "CDABA" temp = str1.str1 = "ABACDABACD" Since str2 is a substring of temp, str1 and str2 are rotations of each other.
Strings are rotations of each other
Library Functions Used:
strstr finds a sub-string within a string.
Prototype: char * strstr(const char *s1, const char *s2);
See http://www.lix.polytechnique.fr/Labo/Leo.Liberti/public/computing/prog/c/C/MAN/strstr.htm for more details
strncat concatenate two strings
Prototype: char *strcat(char *dest, const char *src);
See http://www.lix.polytechnique.fr/Labo/Leo.Liberti/public/computing/prog/c/C/MAN/strcat.htm for more details
Time Complexity: Time complexity of this problem depends on the implementation of strstr function.
If implementation of strstr is done using KMP matcher then complexity of the above program is (-)(n1 + n2) where n1 and n2 are lengths of strings. KMP matcher takes (-)(n) time to find a substrng in a string of length n where length of substring is assumed to be smaller than the string.
GeeksforGeeks has prepared a complete interview preparation course with premium videos, theory, practice problems, TA support and many more features. Please refer Placement 100 for details
- Check if strings are rotations of each other or not | Set 2
- Number of strings which starts and ends with same character after rotations
- Program to check if two strings are same or not
- Minimum circular rotations to obtain a given numeric string by avoiding a set of given strings
- Check if two numbers are bit rotations of each other or not
- Check if all rows of a matrix are circular rotations of each other
- Meta Strings (Check if two strings can become same after a swap in one string)
- Check whether all the rotations of a given number is greater than or equal to the given number or not
- Check if two strings are k-anagrams or not
- Check whether Strings are k distance apart or not
- Check if two strings are permutation of each other
- Check whether two strings are anagram of each other
- Check if two given strings are isomorphic to each other
- Check duplicates in a stream of strings
- Check if two strings have a common substring