Sum of all Matrix elements

Given a matrix mat[][], the task is to find the sum of all the elements of the matrix.

Examples:

Input: mat[][] = {{1, 2, 3}, {4, 5, 6}}
Output: 21
Explanation: Here sum of all element = 1 + 2 + 3 + 4 + 5 + 6 = 21
Input: mat[][] = {{4, 5, 3, 2}, {9, 5, 6, 2}, {1, 5, 3, 5}}
Output: 50
Explanation: Here sum of all element = 4 + 5 + 3 + 2 + 9 + 5 + 6 + 2 + 1 + 5 + 3 + 5 = 50

Try It Yourself

Using Matrix Traversal – O(n * m) Time and O(1) Space

The idea is to traverse every element of the matrix and keep adding them to a running sum.. This direct approach works efficiently as we must visit all elements anyway to compute the sum.

Initialize a variable to store the total sum
Traverse each row and column of the matrix using nested loops
Add every element to the sum while traversing

C++

#include <bits/stdc++.h>
using namespace std;

// Function to find sum of all elements of matrix
int sumOfMatrix(vector<vector<int> > &mat)
{
    // Initialise sum = 0 to store sum
    // of each element
    int sum = 0;

    int n = mat.size();
    int m = mat[0].size();

    // Traverse in each row
    for (int i = 0; i < n; i++) {

        // Traverse in column of that row
        for (int j = 0; j < m; j++) {

            // Add element in variable sum
            sum += mat[i][j];
        }
    }

    // Return sum of matrix
    return sum;
}

// Driver Code
int main()
{
    // Input Data
    vector<vector<int> > mat = { { 4, 5, 3, 2 },
                                 { 9, 5, 6, 2 },
                                 { 1, 5, 3, 5 } };

    // Function call
    cout << sumOfMatrix(mat) << endl;

    return 0;
}

Java

import java.util.*;

class GFG {

    // Function to find sum of all elements of matrix
    static int sumOfMatrix(int[][] mat)
    {
        // Initialise sum = 0 to store sum
        // of each element
        int sum = 0;

        int n = mat.length;
        int m = mat[0].length;

        // Traverse in each row
        for (int i = 0; i < n; i++) {

            // Traverse in column of that row
            for (int j = 0; j < m; j++) {

                // Add element in variable sum
                sum += mat[i][j];
            }
        }

        // Return sum of matrix
        return sum;
    }

    // Driver Code
    public static void main(String[] args)
    {
        // Input Data
        int[][] mat = {
            {4, 5, 3, 2},
            {9, 5, 6, 2},
            {1, 5, 3, 5}
        };

        // Function call
        System.out.println(sumOfMatrix(mat));
    }
}

Python

# Function to find sum of all elements of matrix
def sumOfMatrix(mat):

    # Initialise sum = 0 to store sum
    # of each element
    total = 0

    n = len(mat)
    m = len(mat[0])

    # Traverse in each row
    for i in range(n):

        # Traverse in column of that row
        for j in range(m):

            # Add element in variable sum
            total += mat[i][j]

    # Return sum of matrix
    return total


# Driver Code
# Input Data
mat = [
    [4, 5, 3, 2],
    [9, 5, 6, 2],
    [1, 5, 3, 5]
]

# Function call
print(sumOfMatrix(mat))

using System;

class GFG {

    // Function to find sum of all elements of matrix
    static int sumOfMatrix(int[,] mat)
    {
        // Initialise sum = 0 to store sum
        // of each element
        int sum = 0;

        int n = mat.GetLength(0);
        int m = mat.GetLength(1);

        // Traverse in each row
        for (int i = 0; i < n; i++) {

            // Traverse in column of that row
            for (int j = 0; j < m; j++) {

                // Add element in variable sum
                sum += mat[i, j];
            }
        }

        // Return sum of matrix
        return sum;
    }

    // Driver Code
    public static void Main()
    {
        // Input Data
        int[,] mat = {
            {4, 5, 3, 2},
            {9, 5, 6, 2},
            {1, 5, 3, 5}
        };

        // Function call
        Console.WriteLine(sumOfMatrix(mat));
    }
}

JavaScript

// Function to find sum of all elements of matrix
function sumOfMatrix(mat)
{
    // Initialise sum = 0 to store sum
    // of each element
    let sum = 0;

    let n = mat.length;
    let m = mat[0].length;

    // Traverse in each row
    for (let i = 0; i < n; i++) {

        // Traverse in column of that row
        for (let j = 0; j < m; j++) {

            // Add element in variable sum
            sum += mat[i][j];
        }
    }

    // Return sum of matrix
    return sum;
}

// Driver Code
// Input Data
let mat = [
    [4, 5, 3, 2],
    [9, 5, 6, 2],
    [1, 5, 3, 5]
];

// Function call
console.log(sumOfMatrix(mat));

Output

Sum of all Matrix elements

Using Matrix Traversal – O(n * m) Time and O(1) Space

Explore