LeetCode 1351. Count Negative Numbers in a Sorted Matrix - Python

LeetCode 1351. Count Negative Numbers in a Sorted Matrix

 

Given a m * n matrix grid which is sorted in non-increasing order both row-wise and column-wise.

Return the number of negative numbers in grid.

• m == grid.length
• n == grid[i].length
• 1 <= m, n <= 100
• -100 <= grid[i][j] <= 100

Example 1:

Input: grid = [[4,3,2,-1],[3,2,1,-1],[1,1,-1,-2],[-1,-1,-2,-3]]
Output: 8
Explanation: There are 8 negatives number in the matrix.

Example 2:

Input: grid = [[3,2],[1,0]]
Output: 0

Example 3:

Input: grid = [[1,-1],[-1,-1]]
Output: 3

 

 

Solution:

class Solution:
    def countNegatives(self,grid):
        count = 0 
        grid_sum = sum(grid, [])
        for i in grid_sum:
            if i < 0:
                count += 1
        return count

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