C++ Program to Check if all rows of a matrix are circular rotations of each other
Given a matrix of n*n size, the task is to find whether all rows are circular rotations of each other or not.
Examples:
Input: mat[][] = 1, 2, 3
3, 1, 2
2, 3, 1
Output: Yes, All rows are rotated permutationof each other.
Input: mat[3][3] = 1, 2, 33, 2, 1
1, 3, 2
Output: No , As 3, 2, 1 is not a rotated or circular permutation of 1, 2, 3
The idea is based on below article.
A Program to check if strings are rotations of each other or not
Steps :
- Create a string of first row elements and concatenate the string with itself so that string search operations can be efficiently performed. Let this string be str_cat.
- Traverse all remaining rows. For every row being traversed, create a string str_curr of current row elements. If str_curr is not a substring of str_cat, return false.
- Return true.
Below is the implementation of above steps.
C++
// C++ program to check if all rows of a matrix // are rotations of each other #include <bits/stdc++.h> using namespace std; const int MAX = 1000; // Returns true if all rows of mat[0..n-1][0..n-1] // are rotations of each other. bool isPermutedMatrix( int mat[MAX][MAX], int n) { // Creating a string that contains elements of first // row. string str_cat = "" ; for ( int i = 0 ; i < n ; i++) str_cat = str_cat + "-" + to_string(mat[0][i]); // Concatenating the string with itself so that // substring search operations can be performed on // this str_cat = str_cat + str_cat; // Start traversing remaining rows for ( int i=1; i<n; i++) { // Store the matrix into vector in the form // of strings string curr_str = "" ; for ( int j = 0 ; j < n ; j++) curr_str = curr_str + "-" + to_string(mat[i][j]); // Check if the current string is present in // the concatenated string or not if (str_cat.find(curr_str) == string::npos) return false ; } return true ; } // Drivers code int main() { int n = 4 ; int mat[MAX][MAX] = {{1, 2, 3, 4}, {4, 1, 2, 3}, {3, 4, 1, 2}, {2, 3, 4, 1} }; isPermutedMatrix(mat, n)? cout << "Yes" : cout << "No" ; return 0; } |
Output
Yes
Time complexity : O(n3)
Auxiliary Space : O(n)
Please refer complete article on Check if all rows of a matrix are circular rotations of each other for more details!
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