SQUARE MATRIX

• Problem Description

  
  Given a square matrix of size NN, calculate the absolute difference between the sums of its diagonals. 
  
  Input
  The first line contains a single integer N. The next N lines denote the matrix's rows, with each line containing N space-separated integers describing the columns.
  
  Output
  Print the absolute difference between the two sums of the matrix's diagonals as a single integer.
  
  Constraints
  1<=N<=10
  
  Explanation
  The primary diagonal is: 
  11
  5
  -12
  Sum across the primary diagonal: 11 + 5 - 12 = 4
  The secondary diagonal is:
  4
  5
  10
  
  Sum across the secondary diagonal: 4 + 5 + 10 = 19 
  Difference: |4 - 19| = 15

• CODING ARENA

• #include <stdio.h>

  #include<math.h>

  #include<stdlib.h>

  int main()

  {

    int n,sum=0,i,j,sum1=0,difference=0;

    scanf("%d",&n);

    int a[100][100];

    for(i=0;i<n;i++)

    {

      for(j=0;j<n;j++)

      {

        scanf("%d",&a[i][j]);

      }

    }

    for(i=0;i<n;i++)

    {

      for(j=0;j<n;j++)

      {

        if(i==j)

          sum=sum+a[i][j];

      }

    }

    for(i=0;i<n;i++)

    {

      for(j=0;j<n;j++)

      {

        if(i==n-j-1)

          sum1=sum1+a[i][j];

      }

    }

    difference=abs(sum-sum1);

    printf("%d",difference);

    return 0;

  }

• Test Case 1

  
  Input (stdin)

  3
  
  11 2 4
  
  4 5 6
  
  10 8 -12
  
  

  Expected Output

  15

• Test Case 2

  
  Input (stdin)

  3
  
  4 5 5
  
  3 9 6
  
  7 4 6
  
  

  Expected Output

  2