Count Negative Numbers in a Sorted Matrix using Python

In this example, we will count Negative Numbers in a Column-Wise and Row-Wise Sorted Matrix. At first, we will create a matrix ?

mat = [
   [-1, 3, 5, 7],
   [-6, -3, 1, 4],
   [-5, -1, -10, 12]
]

Pass the matrix to a custom function and use nested for loop ?

def negativeFunc(mat, r, c):
   count = 0
      for i in range(r):
         for j in range(c):
            if mat[i][j] < 0:
	       count += 1
	    else:
	   break
return count

Above, in the for loop each matrix element is checked for negative values. On finding a negative value, the count increments.

Here's the complete example ?

Example

# The matrix must be sorted in ascending order, else it won't work
def negativeFunc(mat, r, c):
	count = 0
	for i in range(r):
		for j in range(c):
			if mat[i][j] < 0:
				count += 1
			else:
				break
	return count

# Driver code
mat = [
	[-1, 3, 5, 7],
	[-6, -3, 1, 4],
	[-5, -1, -10, 12]
]

print("Matrix = ",mat)
print("Count of Negative Numbers = ",negativeFunc(mat, 3, 4))


Matrix =  [[-1, 3, 5, 7], [-6, -3, 1, 4], [-5, -1, -10, 12]]
Count of Negative Numbers =  6

Output

Matrix =  [[-1, 3, 5, 7], [-6, -3, 1, 4], [-5, -1, -10, 12]]
Count of Negative Numbers =  6