Frosty Cells

Easy

A weather station keeps an m × n table of temperatures temps. The table is ordered: within every row the values never increase from left to right, and within every column they never increase from top to bottom. Return the number of cells where the temperature is below zero. Can you do it in O(m + n)?

Example 1

temps=[[6, 2, -1], [3, 0, -4], [-2, -3, -5]] → 5

Below zero: -1 in the first row, -4 in the second and all three values in the third, 5 in total.

Example 2

temps=[[8, 5], [4, 1]] → 0

There are no negative values.

Example 3

temps=[[-1]] → 1

The only cell is below zero.

Constraints

1 ≤ m, n ≤ 100
−100 ≤ temps[i][j] ≤ 100
Every row and every column is non-increasing

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Array Binary Search Matrix

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Input

temps=[[6, 2, -1], [3, 0, -4], [-2, -3, -5]]

Expected

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