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.
C++
// C++ program to check if a string // is two time rotation of another string. #include<bits/stdc++.h> using namespace std;
// Function to check if string2 is // obtained by string 1 bool isRotated(string str1,
string str2)
{ if (str1.length() != str2.length())
return false ;
if (str1.length()<2){
return str1.compare(str2) == 0;
}
string clock_rot = "" ;
string anticlock_rot = "" ;
int len = str2.length();
// Initialize string as anti-clockwise
// rotation
anticlock_rot = anticlock_rot +
str2.substr(len-2, 2) +
str2.substr(0, len-2) ;
// Initialize string as clock wise
// rotation
clock_rot = clock_rot +
str2.substr(2) +
str2.substr(0, 2) ;
// check if any of them is equal
// to string1
return (str1.compare(clock_rot) == 0 ||
str1.compare(anticlock_rot) == 0);
} // Driver code int main()
{ string str1 = "geeks" ;
string str2 = "eksge" ;
isRotated(str1, str2) ? cout << "Yes"
: cout << "No" ;
return 0;
} |
Output:
Yes
Time Complexity: O(n), where n is the size of the given string.
Please refer complete article on Check if a string can be obtained by rotating another string 2 places for more details!