# How to find unique elements in matrix in C++

In this tutorial, we will learn how to find unique elements in a matrix in C++ with an example and algorithm.

The elements which appear only one time in a matrix are unique elements of that matrix.

## How to find unique elements in a matrix

let’s take an example to find a unique element in a matrix manually.

**Example: **

Consider a matrix of od size 3*4 input matrix: 1 2 3 6 5 1 8 3 5 7 8 9 so, there are 3*4 = 12 elements in the - 1,2,3,5,6,7,8,9 in which 1,3,5,8 are repeated elements and 2,6,7 and 9 are not repeated in the matrix. Therefore, the unique elements in the array are 2,6,7,9.

## Algorithm

- Declare and initialize a matrix of m*n. (where m and n are the lengths of row and column of matrix).
- Find the largest number in the matrix.
- declare a temporary array of size equal to largest lumber in the matrix with an increment of 1.
- start an outer loop from
**i = 0 to m**and an inner loop from**j = 0 to n**inside the outer loop. - For each element in the matrix increment the value by one at the temporary array by using the element as an index number.
- Traverse the temporary array and search for value 1 in the temporary array. when everyone is the encounter, print the index number.
- if no value in the matrix is one, then no unique element present in the array.

## C++ program to find unique elements in a matrix

#include<bits/stdc++.h> using namespace std; //function to calculate unique element int FindUnique(int matrix[50][50], int m, int n) { int max = 0, flag = 0; for(int i = 0; i < m; i++) for(int j = 0; j < n; j++) // Find maximum element in // a matrix if(max < matrix[i][j]) max = matrix[i][j]; // Take 1-D array of (maximum + 1) size int temp[max + 1] = {0}; //counting the number of repetation of number available //by index value as that number for(int i = 0 ; i < m; i++) for(int j = 0; j < n; j++) temp[matrix[i][j]]++; //print unique element cout<<"Unique numbers are: "; for(int i = 1; i <= max; i++) if(temp[i] == 1) cout << i << " "; flag = 1; if(!flag){ cout << " No unique element in the matrix"; } } // Driver program int main() { int matrix[50][50], m, n; //taking input for the length of row and column. cout<<"Enter the length of the row: "; cin>>m; cout<<"Enther the length of the column: "; cin>>n; //input the elements of matrix cout<<"\nEnter the lements of matrix:\n "; for(int i = 0;i < m;i++) for(int j = 0; j < n; j++) cin>>matrix[i][j]; // function that calculate unique element FindUnique(matrix, m, n); return 0; }

**Output: **

Enter the length of the row: 3 Enther the length of the column: 4 Enter the elements of marix: 1 2 3 6 5 1 8 3 5 7 8 9 Unique numbers are: 2 6 7 9

**Time complexity: **O(m*n) where m and n is the size of row and column of the matrix.

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