Sum of Zig-Zag

Write a C++ program to find the sum of Zig-Zag pattern in a given matrix.

INPUT & OUTPUT FORMAT:

Input consists of 2 integers and 1 2D-array. Integers correspond to the size of rows and columns.

SAMPLE INPUT:

3

3

1 2 3

4 5 6

7 8 9

SAMPLE OUTPUT:

Sum of Zig-Zag pattern is 35

SAMPLE INPUT:

2

2

1 2 

4 5 

SAMPLE OUTPUT:

Sum of Zig-Zag pattern is 12

SOLUTION:

#include<iostream>

using namespace std;

int main()

{

  int r, c, i, j, sum = 0;

  cin>>r>>c;

  int mat[r][c];

  for(i = 0; i < r; i++){

    for(j = 0; j < c; j++){

      cin>>mat[i][j];

    }

  }

  for(j = 0; j < c; j++){

     sum += mat[0][j];

  }

  for(i = 1; i <= r-2; i++){

    for(j = c-2; j > 0; j--){

      sum += mat[i][j];

    }

  }

  for(j = 0; j < c; j++){

    sum += mat[r-1][j];

  }

  cout<<"Sum of Zig-Zag pattern is "<<sum;

  return 0;

}