Question
Given a m x n
matrix grid
which is sorted in non-increasing order both row-wise and column-wise, return the number of negative numbers in grid
.
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
Constraints:
m == grid.length
n == grid[i].length
1 <= m, n <= 100
-100 <= grid[i][j] <= 100
Follow up: Could you find an O(n + m)
solution?
Python Solution
class Solution: def countNegatives(self, grid: List[List[int]]) -> int: m=len(grid) n=len(grid[0]) r,c,neg_count = 0,n-1,0 while r<m and c>=0: if grid [r][c]<0: neg_count = neg_count + m-r c-=1 else: r+=1 return (neg_count)