Find unique elements in a matrix
Given a matrix mat[][] having n rows and m columns. We need to find unique elements in matrix i.e, those elements which are not repeated in the matrix or those elements whose frequency is 1.
Examples:
Input : 20 15 30 2
2 3 5 30
6 7 6 8
Output : 3 20 5 7 8 15
Input : 1 2 3
5 6 2
1 3 5
6 2 2
Output : No unique element in the matrix
Follow these steps to find unique element:
1. Create an empty hash table or dictionary.
2. Traverse through all the elements of the matrix
3. If element is present in the dictionary, then increment its count
4. Otherwise insert element with value = 1.
C++
// C++ program to find unique // element in matrix #include<bits/stdc++.h> using namespace std; #define R 4 #define C 4 // function that calculate unique element int unique(int mat[R][C], int n, int m) { int maximum = 0, flag = 0; for(int i = 0; i < n; i++) for(int j = 0; j < m; j++) // Find maximum element in // a matrix if(maximum < mat[i][j]) maximum = mat[i][j]; // Take 1-D array of (maximum + 1) // size int b[maximum + 1] = {0}; for(int i = 0 ; i < n; i++) for(int j = 0; j < m; j++) b[mat[i][j]]++; //print unique element for(int i = 1; i <= maximum; i++) if(b[i] == 1) cout << i << " "; flag = 1; if(!flag){ cout << "No unique element in the matrix"; } } // Driver program int main() { int mat[R][C] = {{ 1, 2, 3, 20}, {5, 6, 20, 25}, {1, 3, 5, 6}, {6, 7, 8, 15}}; // function that calculate unique element unique(mat, R, C); return 0; } // This code is contributed by Naman_Garg. |
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Java
// Java program to find unique // element in matrix class GFG { static int R = 4, C = 4; // function that calculate // unique element static void unique(int mat[][], int n, int m) { int maximum = 0, flag = 0; for(int i = 0; i < n; i++) for(int j = 0; j < m; j++) // Find maximum element // in a matrix if(maximum < mat[i][j]) maximum = mat[i][j]; // Take 1-D array of // (maximum + 1) size int b[] = new int [maximum + 1]; for(int i = 0 ; i < n; i++) for(int j = 0; j < m; j++) b[mat[i][j]]++; //print unique element for(int i = 1; i <= maximum; i++) if(b[i] == 1) System.out.print(i + " "); flag = 1; if(flag == 0) { System.out.println("No unique element " + "in the matrix"); } } // Driver Code public static void main(String args[]) { int mat[][] = {{1, 2, 3, 20}, {5, 6, 20, 25}, {1, 3, 5, 6}, {6, 7, 8, 15}}; // function that calculate // unique element unique(mat, R, C); } } // This code is contributed // by Arnab Kundu |
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Python3
# Python 3 program to find unique # element in matrix def unique(mat, n, m): maximum = 0; flag = 0 for i in range(0, n): for j in range(0, m): # Find maximum element in # a matrix if(maximum < mat[i][j]): maximum = mat[i][j]; uniqueElementDict = [0] * (maximum + 1) # loops to traverse through the matrix for i in range(0, n): for j in range(0, m): uniqueElementDict[mat[i][j]] += 1 # Print all those keys whose count is 1 for key in range(maximum + 1): if uniqueElementDict[key] == 1: print (key, end = " ") flag = 1 if(flag == 0): print("No unique element in the matrix") # Driver Code mat = [[1, 2, 3, 20], [5, 6, 20, 25], [1, 3, 5, 6], [6, 7, 8, 15]] n = 4m = 4unique(mat, n, m) |
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C#
// C# program to find unique // element in matrix using System; class GFG { static int R = 4, C = 4; // function that calculate // unique element static void unique(int [,]mat, int n, int m) { int maximum = 0, flag = 0; for(int i = 0; i < n; i++) for(int j = 0; j < m; j++) // Find maximum element // in a matrix if(maximum < mat[i, j]) maximum = mat[i, j]; // Take 1-D array of // (maximum + 1) size int []b = new int [maximum + 1]; for(int i = 0 ; i < n; i++) for(int j = 0; j < m; j++) b[mat[i, j]]++; // print unique element for(int i = 1; i <= maximum; i++) if(b[i] == 1) Console.Write(i + " "); flag = 1; if(flag == 0) { Console.WriteLine("No unique element " + "in the matrix"); } } // Driver Code public static void Main() { int [,]mat = {{1, 2, 3, 20}, {5, 6, 20, 25}, {1, 3, 5, 6}, {6, 7, 8, 15}}; // function that calculate // unique element unique(mat, R, C); } } // This code is contributed // by Subhadeep |
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PHP
<?php // PHP program to find unique // element in matrix $R = 4; $C = 4; // function that calculate unique element function unique($mat, $n, $m) { $maximum = 0; $flag = 0; for($i = 0; $i < $n; $i++) for($j = 0; $j < $m; $j++) // Find maximum element in // a matrix if($maximum < $mat[$i][$j]) $maximum = $mat[$i][$j]; // Take 1-D array of (maximum + 1) // size $b = array(); for($j = 0; $j < $maximum + 1; $j++) $b[$j] = 0; for($i = 0 ; $i < $n; $i++) for($j = 0; $j < $m; $j++) $b[$mat[$i][$j]]++; // print unique element for($i = 1; $i <= $maximum; $i++) if($b[$i] == 1) echo "$i "; $flag = 1; if(!$flag) { echo "No unique element in the matrix"; } } // Driver Code $mat = array(array(1, 2, 3, 20), array(5, 6, 20, 25), array(1, 3, 5, 6), array(6, 7, 8, 15)); // function that calculate unique element unique($mat, $R, $C); // This code is contributed by iAyushRaj ?> |
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Output:
2 7 8 25 15
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