Javascript 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 permutation of each other. Input: mat[3][3] = 1, 2, 3 3, 2, 1 1, 3, 2 Output: No Explanation : As 3, 2, 1 is not a rotated or circular permutation of 1, 2, 3
The idea is based on the 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 the above steps.
Javascript
<script> // Javascript program to check if all rows of a matrix // are rotations of each other // Returns true if all rows of mat[0..n-1][0..n-1] // are rotations of each other. function isPermutedMatrix(mat, n) { // Creating a string that contains // elements of first row. let str_cat = "" ; for (let i = 0; i < n; i++) { str_cat = str_cat + "-" + (mat[0][i]).toString(); } // 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 (let i = 1; i < n; i++) { // Store the matrix into vector in the form // of strings let curr_str = "" ; for (let j = 0; j < n; j++) { curr_str = curr_str + "-" + (mat[i][j]).toString(); } // Check if the current string is present in // the concatenated string or not if (str_cat.includes(curr_str)) { return true ; } } return false ; } // Drivers code let n = 4; let mat = [ [ 1, 2, 3, 4 ], [ 4, 1, 2, 3 ], [ 3, 4, 1, 2 ], [ 2, 3, 4, 1 ] ]; if (isPermutedMatrix(mat, n)) document.write( "Yes" ) else document.write( "No" ) // This code is contributed by rag2127 </script> |
Output:
Yes
Time Complexity: O(n^3)
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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