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Find row with maximum sum in a Matrix
• Last Updated : 10 Oct, 2019

Given an N*N matrix. The task is to find the index of a row with the maximum sum. That is the row whose sum of elements is maximum.

Examples:

Input : mat[][] = {
{ 1, 2, 3, 4, 5 },
{ 5, 3, 1, 4, 2 },
{ 5, 6, 7, 8, 9 },
{ 0, 6, 3, 4, 12 },
{ 9, 7, 12, 4, 3 },
};
Output : Row 3 has max sum 35

Input : mat[][] = {
{ 1, 2, 3 },
{ 4, 2, 1 },
{ 5, 6, 7 },
};
Output : Row 3 has max sum 18

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

The idea is to traverse the matrix row-wise and find the sum of elements in each row and check for every row if current sum is greater than the maximum sum obtained till the current row and update the maximum_sum accordingly.

Below is the implementation of the above approach:

## C++

 // C++ program to find row with // max sum in a matrix #include using namespace std;    #define N 5 // No of rows and column    // Function to find the row with max sum pair colMaxSum(int mat[N][N]) {     // Variable to store index of row     // with maximum     int idx = -1;        // Variable to store max sum     int maxSum = INT_MIN;        // Traverse matrix row wise     for (int i = 0; i < N; i++) {         int sum = 0;            // calculate sum of row         for (int j = 0; j < N; j++) {             sum += mat[i][j];         }            // Update maxSum if it is less than         // current sum         if (sum > maxSum) {             maxSum = sum;                // store index             idx = i;         }     }        pair res;        res = make_pair(idx, maxSum);        // return result     return res; }    // Driver code int main() {        int mat[N][N] = {         { 1, 2, 3, 4, 5 },         { 5, 3, 1, 4, 2 },         { 5, 6, 7, 8, 9 },         { 0, 6, 3, 4, 12 },         { 9, 7, 12, 4, 3 },     };        pair ans = colMaxSum(mat);        cout << "Row " << ans.first + 1 << " has max sum "          << ans.second;        return 0; }

## Java

 // Java program to find row with // max sum in a matrix import java.util.ArrayList;    class MaxSum {     public static int N;        static ArrayList colMaxSum(int mat[][])     {         // Variable to store index of row         // with maximum         int idx = -1;            // Variable to store maximum sum         int maxSum = Integer.MIN_VALUE;            // Traverse the matrix row wise         for (int i = 0; i < N; i++)          {             int sum = 0;             for (int j = 0; j < N; j++)             {                 sum += mat[i][j];             }                // Update maxSum if it is less than             // current row sum             if (maxSum < sum)             {                 maxSum = sum;                    // store index                 idx = i;             }         }                    // Arraylist to store values of index         // of maximum sum and the maximum sum together         ArrayList res = new ArrayList<>();         res.add(idx);         res.add(maxSum);            return res;     }        // Driver code     public static void main(String[] args)     {         N = 5;         int[][] mat = {              { 1, 2, 3, 4, 5 },              { 5, 3, 1, 4, 2 },              { 5, 6, 7, 8, 9 },              { 0, 6, 3, 4, 12 },             { 9, 7, 12, 4, 3 },         };         ArrayList ans = colMaxSum(mat);         System.out.println("Row "+ (ans.get(0)+1)+ " has max sum "         + ans.get(1));     } }    // This code is contributed by Vivekkumar Singh

## Python3

 # Python3 program to find row with  # max sum in a matrix  import sys    N = 5 # No of rows and column     # Function to find the row with max sum  def colMaxSum(mat):        # Variable to store index of row      # with maximum      idx = -1        # Variable to store max sum      maxSum = -sys.maxsize        # Traverse matrix row wise      for i in range(0, N):          sum = 0            # calculate sum of row          for j in range(0, N):              sum += mat[i][j]             # Update maxSum if it is less than          # current sum          if (sum > maxSum):             maxSum = sum                # store index              idx = i         res = [idx, maxSum]        # return result      return res    # Driver code  mat = [[ 1, 2, 3, 4, 5],         [ 5, 3, 1, 4, 2],         [ 5, 6, 7, 8, 9],         [ 0, 6, 3, 4, 12],         [ 9, 7, 12, 4, 3]]     ans = colMaxSum(mat) print("Row", ans[0] + 1, "has max sum", ans[1])    # This code is contributed by Sanjit_Prasad

## C#

 // C# program to find row with // max sum in a matrix using System; using System.Collections.Generic;     public class MaxSum {     public static int N;        static List colMaxSum(int [,]mat)     {         // Variable to store index of row         // with maximum         int idx = -1;            // Variable to store maximum sum         int maxSum = int.MinValue;            // Traverse the matrix row wise         for (int i = 0; i < N; i++)          {             int sum = 0;             for (int j = 0; j < N; j++)             {                 sum += mat[i, j];             }                // Update maxSum if it is less than             // current row sum             if (maxSum < sum)             {                 maxSum = sum;                    // store index                 idx = i;             }         }                    // Arraylist to store values of index         // of maximum sum and the maximum sum together         List res = new List();         res.Add(idx);         res.Add(maxSum);            return res;     }        // Driver code     public static void Main(String[] args)     {         N = 5;         int[,] mat = {              { 1, 2, 3, 4, 5 },              { 5, 3, 1, 4, 2 },              { 5, 6, 7, 8, 9 },              { 0, 6, 3, 4, 12 },             { 9, 7, 12, 4, 3 },         };         List ans = colMaxSum(mat);         Console.WriteLine("Row "+ (ans[0]+1)+ " has max sum "         + ans[1]);     } }    // This code has been contributed by 29AjayKumar

Output:

Row 3 has max sum 35

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