# Task
 Given a rectangular `matrix` and integers `a` and `b`, consider the union of the ath row and the bth (both 0-based) column of the `matrix`. Return sum of all elements of that union.

# Example

 For
```
matrix = [[1, 1, 1, 1], 
          [2, 2, 2, 2], 
          [3, 3, 3, 3]]
a = 1 and b = 3 ```
the output should be `12`.

 Here `(2 + 2 + 2 + 2) + (1 + 3) = 12`.

# Input/Output


 - `[input]` 2D integer array `matrix`

    2-dimensional array of integers representing a rectangular matrix.

    Constraints: `1 ≤ matrix.length ≤ 5, 1 ≤ matrix[0].length ≤ 5, 1 ≤ matrix[i][j] ≤ 100.`
    

 - `[input]` integer `a`

  A non-negative integer less than the number of matrix rows.

   Constraints: `0 ≤ a < matrix.length.`
   
   
 - `[input]` integer `b`

   A non-negative integer less than the number of matrix columns.

   Constraints: `0 ≤ b < matrix[i].length. `


 - `[output]` an integer

Difficulty: EASY
Starter code: def crossing_sum(matrix, row, col):
	

Solutions:
def crossing_sum(matrix, row, col):
	return sum(matrix[row]) + sum((line[col] for line in matrix)) - matrix[row][col]


def crossing_sum(a, b, c):
	return sum(a[b]) + sum((x[c] for x in a)) - a[b][c]


def crossing_sum(matrix, row, col):
	return sum(matrix[row]) + sum((i[col] for i in matrix[:row] + matrix[row + 1:]))


def crossing_sum(matrix, row, col):
	mat_tr = [[i[j] for i in matrix] for j in range(len(matrix[0]))]
	return sum(matrix[row] + mat_tr[col]) - matrix[row][col]


def crossing_sum(matrix, row, col):
	return sum(matrix[row]) + sum((matrix[i][col] for i in range(len(matrix)))) - matrix[row][col]


def crossing_sum(mx, r, c):
	return sum(mx[r] + [x[c] for x in mx[:r] + mx[r + 1:]])


crossing_sum = lambda m, r, c: sum(m[r]) + sum((l[c] for (i, l) in enumerate(m) if i != r))


def crossing_sum(matrix, row, col):
	a = matrix[row]
	b = [i[col] for (num, i) in enumerate(matrix) if num != row]
	return sum(a) + sum(b)


def crossing_sum(matrix, row, col):
	return sum(matrix[row]) + sum([matrix[a][col] for a in range(len(matrix)) if a != row])