Row Sum

1 <= A.size() <= 10^3
1 <= A[i].size() <= 10^3
1 <= A[i][j] <= 10^3

First argument A is a 2D array of integers.(2D matrix).

Return an array containing row-wise sums of original matrix.

Input 1:
[1,2,3,4]
[5,6,7,8]
[9,2,3,4]

Output 1:
[10,26,18]

Explanation 1:
Row 1 = 1+2+3+4 = 10
Row 2 = 5+6+7+8 = 26
Row 3 = 9+2+3+4 = 18