Skip to content
Related Articles

Related Articles

C++ Program for Minimum rotations required to get the same string

Improve Article
Save Article
  • Last Updated : 11 Jan, 2022
Improve Article
Save Article

Given a string, we need to find the minimum number of rotations required to get the same string.

Examples:

Input : s = "geeks"
Output : 5

Input : s = "aaaa"
Output : 1

The idea is based on below post.

A Program to check if strings are rotations of each other or not


Step 1 :
Initialize result = 0 (Here result is count of rotations)
Step 2 : Take a temporary string equals to original string concatenated with itself.
Step 3 : Now take the substring of temporary string of size same as original string starting from second character (or index 1).
Step 4 : Increase the count.
Step 5 : Check whether the substring becomes equal to original string. If yes, then break the loop. Else go to step 2 and repeat it from the next index.

C/C++




// C++ program to determine minimum number
// of rotations required to yield same
// string.
#include <iostream>
using namespace std;
  
// Returns count of rotations to get the
// same string back.
int findRotations(string str)
{
    // tmp is the concatenated string.
    string tmp = str + str;
    int n = str.length();
  
    for (int i = 1; i <= n; i++) {
  
        // substring from i index of original
        // string size.
        string substring = tmp.substr(i, str.size());
  
        // if substring matches with original string
        // then we will come out of the loop.
        if (str == substring)
            return i;
    }
    return n;
}
  
// Driver code
int main()
{
    string str = "abc";
    cout << findRotations(str) << endl;
    return 0;
}



Output:

3

Time Complexity: O(n2)

Please refer complete article on Minimum rotations required to get the same string for more details!

My Personal Notes arrow_drop_up
Related Articles

Start Your Coding Journey Now!